FlyingScot
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This guide assumes that you already have the basic knowledge necessary to enter the MSI BIOS and navigate the various settings screens. It also assumes that you have already upgraded (or plan to upgrade) to one of the more recent BIOS versions (August 2024 or more recent) that includes microcode 0x125, 0x129 or 0x12B. If you need more background information on these microcode releases, I have summarized them in this post.
I’ve tried to arrange the information in this guide in a way that takes the reader down this rabbit hole we call “undervolting” at a pace that matches their curiosity. At any point along the way, you are free to jump off to the much simpler beginners guide created by CiTay. If you do decide to use CiTay’s guide then I can recommend this example of a before and after case study.
However, if you decide to keep reading then think of the information I present in this guide as both a prelude to Citay’s guide and a “next-steps” knowledge base for those who want (or are curious) to take undervolting to the next level. At a minimum, it might serve as useful reference material once the reader has gained some prior undervolting experience.
[LEVEL ONE KNOWLEDGE]
I've been working on a standardized approach to Raptor Lake voltage tuning. But before I get to that, perhaps we should ask the question "Why do we undervolt?" In the old days, all we talked about was "overclocking." But these days, undervolting is often much more desirable. After all, our PCs are already noisy and hot enough as it is, don't you think?
Reasons to undervolt might include one or more of the following:
[1] Fix a PC with excessive fan noise, especially while running stability tests, benchmarks, heavily multi-threaded applications and playing games.
[2] Increase the longevity of PC components by reducing the kind of degradation that occurs when components get overly hot.
[3] Squeeze every last bit of CPU performance from your PC within the limitations of your existing cooling system.
[4] Less common, but maybe to stabilize an unstable system.
How does silicon quality, referred to as the "silicon lottery," affect your undervolting and overclocking results:
[1] While CPU stability will generally increase with higher voltage levels, a CPU's silicon quality will ultimately have a Core Frequency (Core Ratio) "wall." This means that you will not be able to increase your CPU's core frequency no matter how much voltage you feed it. In some cases, the quality of a single P-Core or E-Core can determine the maximum frequency a CPU can operate at and still remain stable.
[2] When undervolting is the objective, the same frequency-to-voltage relationship will apply. Your CPU's silicon quality will ultimately determine the minimum voltage that each core frequency (Core Ratio) can operate at and still remain stable.
[3] CPU temperature has a direct effect on the minimum voltage your CPU will require in order to remain stable at a given frequency. A CPU's temperature will typically increase in direct relationship to the power consumption (Watts). It is also influenced by the quality of the silicon (i.e. voltage leakage), the ambient temperature of your room, the CPU cooler performance and the case cooling performance.
A quick note: Don't forget that your case cooling performance (in addition to your CPU cooler) can have a direct effect on both CPU temperatures and overall system stability. In particular, cases with solid front panels plus front mounted fans are particularly problematic when it comes to component temperatures. These cases can easily create a "negative pressure" environment, basically where more air is exiting the case than entering the case. Symptoms of a negative pressure condition include unusually high motherboard chipset (e.g. Z690, Z790) temperatures (>65C) and RAM temperatures (>50C).
If you are relatively unaccustomed to this level of BIOS tuning, please don’t worry if the first time you try to follow these steps (as sequenced) you have to keep stepping back. It might take a little prior knowledge and personal experience before you can more easily make these decisions in the order presented. Hindsight is everything. However, if you have any suggestions on how I might improve this guide, which is still a work-in-progress, then please don’t hesitate to leave a comment in this thread. Cheers!
So without further ado, here are the steps that I think make the most sense based upon watching two dozen people struggle with this effort. I've tried to lay out a step-by-step process that (a) provides some important background information for beginners, and (b) side-steps any potential conflicts caused by doing things in the wrong order.
Background Information
Step 1a: Selecting the best CPU Cooler Tuning preset requires a certain level of knowledge and experience, and in some ways is an emotional decision. For example, do you really trust Intel and MSI to pick the best defaults for your unique CPU and usage case? If you are new to tuning then the answer is probably ”Yes!” However, as you gain more tuning expertise, you will likely want to take more direct and preemptive control over the power, voltage and core frequency settings. Selecting a different CPU Cooler Tuning mode can sometimes simplify things. Luckily, however, regardless of the preset you choose (e.g. Intel Defaults, MSI Performance, MSI Unlimited, etc.), you can usually achieve the same end results by using a slightly different combination of defaults and user-overrides - although Intel may make this more difficult with future CPU generations.
Tip: The CPU Cooler Tuning preset you choose can, and will, alter the defaults for the following settings (still a work-in-progress list):
Long Duration Power limit(W) >> [PL1]
Short Duration Power limit(W) >> [PL2]
CPU Current Limit(A) >> [IccMax]
IA CEP Support
IA CEP Support For 14th Gen
TVB Ratio Clipping >> [All i9 CPUs]
TVB Ratio Clipping Enhanced >> [14th gen i9 CPUs ONLY]
CPU Under Voltage Protection >> [Intel whitepaper]
LoadLine Calibration Control (LLC) >> [Auto** value can change behind the scenes]
CPU Lite Load Control
CPU Lite Load [setting] >> [affects the hidden values AC_LL** and DC_LL**]
** "MSI Unlimited" preset appears to select an Auto LLC value of maybe 5, 6, or 7 and then sets AC_LL and DC_LL to “hopefully” match this LLC level, e.g. AC=50/DC=80.
** "MSI Performance" preset ....???
** "Intel Defaults" preset has consistently selected Auto LLC value of 8 and set AC_LL and DC_LL to “hopefully” match this LLC level, normally AC=110/DC=110 (but sometimes 170/170).
Tip: Don’t worry if the above three ** points make no sense to you. It should make more sense after you finish reading my Level Two Knowledge post in this thread.
Tip: Less experienced Raptor Lake tuners should consider starting out with the Intel Defaults preset because it mirrors most of Intel's recommended guidance, including reasonable power limits for your CPU. However, note that the Intel Defaults preset will likely need some serious manual tuning to bring down potentially high voltage and power usage conditions. That's because it has been configured for maximize stability rather than efficiency. More experienced tuners should consider using one of the MSI presets.
Tip: The latest BIOS releases from MSI will likely enable C1E Support by default. This setting was previously set to disabled. In a related point about C-States, be aware that, in some cases, the Package C State Limit setting, especially in the highest sleep states, can cause instability when the CPU is at idle, presumably because voltage drops too low after your undervolting efforts. If you run into idle instability (but all other activities are stable) then either try changing the above C-State settings to be less impactful or simply back off a little on your undervolt. Keep this point in mind for future reference.
Step 1b: The benefits of Current Excursion Protection (“IA CEP Support”) is an ongoing source of debate. The decision to enable or disable CEP is partly an emotional decision in the absence of more convincing data one way or the other. In general, tuning with CEP is often more difficult than tuning without it. It is therefore an important decision that should be made at the earliest stage in the process. As you continue learning more about the role of CEP (keep reading this thread and the recommended links) you may come to better understand both its importance and how to tune with it enabled.
Tip: Be aware that when selecting CPU Cooler Tuning preset “Intel Defaults“, CEP will normally be enabled by default. But when selecting one of the two MSI presets, CEP might be disabled by default.
Step 2a: Do you want to tune your CPU for highly multi-threaded workloads (such as Video processing, Unzipping files, etc.) or non-all-core workloads - like most game engines. This decision can end up driving you crazy if you are trying to maximize benchmark scores and have good gaming temps. For example, Cinebench R23 loves lots of voltage and sky-high power limits (PL1, PL2 and IccMax) - assuming your cooling solution can keep up. On the other hand, games, web browsing, Microsoft Office tasks, etc. are generally low-power activities and therefore allow for much lower voltage (and power limits) to maximum efficiency and run with the coolest temperatures. In the end, you will undoubtedly have to prioritize one over the other. If bragging rights or highly multi-threaded applications are important to you then consider a separate BIOS OC Profile for just those occasions....then have another OC Profile for all other activities, including gaming.
Step 2b: This is an important decision. Do you want Intel to control all the core boosting behavior in order to maximize light load performance (especially single and dual core workloads) but at the risk of more elevated CPU voltages? Or do you want to implement your own individual CPU core frequencies (including the old fashioned All-core frequency approach), which can help to reduce voltages at the expense of slightly reduced light-load performance, e.g. some gaming workloads? Keep in mind that the highest Voltage request (VID) from all the individual IA Cores (both P-Cores and E-Cores), plus the Ring VID, will always decide the voltage the CPU requests from the motherboard’s VRM power module. Due to the Voltage/Frequency (V/F) curves (one for each IA Core) voltage requests (i.e. VIDs) are directly linked to core frequency. If you ask a particular CPU IA Core to hit a higher frequency, it will often require more voltage to remain stable. The same is true if you increase the Ring Ratio. The amount of additional voltage will ultimately depend upon the quality of the silicon in that part of the CPU Die and the temperature you run it at. Conversely, when you lower the peak frequency of a CPU Core (by using a manual core ratio limit or negative turbo offset) you will usually see a lower peak VID request from that particular IA Core.
See the BIOS configuration example below where one of the manual core ratio options is used to lower the maximum P-Core Ratio to 56 and the maximum E-Core Ratio to 41. Notice that in the factory default configuration, P-Core 4 and 5 are considered the “preferred” cores (i.e. better silicon/less voltage needed) and therefore allowed to boost higher than the other cores.
Tip: When implementing manual core ratios, you are forced to use the ”MSI Unlimited” CPU Cooler Tuning preset. This will likely not bother you if you were already using the other MSI preset called “MSI Performance”. However, if you were using the “Intel Defaults” preset, and this is the preset mode you prefer, then you can try to switch back to the “Intel Defaults” preset after making the core ratio change (or any other change that kicks you out of this preset). Some users report that this trick works. But, either way, make sure to revisit Step 1a/1b before moving on to Step 3.
Tip: Of course, you do have a third choice. You could allow the factory boosting behavior to remain in place (see example below) but control the behavior with Turbo offsets, AVX offsets**, Ring offsets, or by disabling Intel Turbo 3.0 that controls single core and dual core boosting for the preferred cores, which is often responsible for the highest peak CPU voltages. Also, while it’s not generally recommended to disable Thermal Velocity Boost (TVB) [i9’s only] and Enhanced Thermal Velocity Boost (eTVB) [14th gen i9’s only], you can in fact alter the factory TVB behavior with manual settings, referred to as OCTVB. In each one of these cases, you can control CPU voltages by manipulating the maximum frequency a core will automatically boost to via the factory algorithms. Again, higher frequency of any one IA Core usually means higher voltage for the entire CPU. With Raptor Lake’s history for degradation, lower voltage is always safer than higher voltage. [This guide may cover Turbo offsets and OCTVB configurations in the future.]
The above table shows the standard factory frequency boosting technologies for the eight (8) P-Cores inside the 14900K SKU. The bottom axis shows the number of active P-Cores and the side axis shows the core frequency.
Key:
Base is the base frequency if you were to disable Intel Turbo 2.0.
TB2 (Turbo Boost 2.0) is limited by the maximum core frequency (per Intel spec. sheet), the main power limits: PL1, PL2, and TAU (how long PL2 can remain active), plus the CPU Package temperature (TJMax), which usually defaults to 100C.
ABT (Adaptive Boost Technology) was first introduced with Rocket Lake. It is not user-configurable for Raptor Lake.
TB3 (Turbo Boost 3.0) was introduced with Alder Lake and is exclusive to i7 and i9 CPUs. It identifies two “preferred“ cores to boost higher under certain conditions. It’s primary focus is to benefit single-threaded applications/events. While not always the case, TB3 can result in the highest voltages seen for your CPU. You can disable this feature in the BIOS.
TVB (Thermal Velocity Boost) was introduced with Comet Lake and is exclusive to i9 CPUs (regardless of whether it shows up in the BIOS). It can be user-configured via a separate OCTVB BIOS submenu. The default behavior is to opportunistically boost core frequencies whenever CPU temperatures are maintained below ~70C.
eTVB (Enhanced Thermal Velocity Boost) works in conjunction with TVB to boost Core Ratio by +1.
** Tip: In the Comet Lake (and earlier) days, AVX offsets could actually lead to instability due to it constantly cutting in an out and causing transient spikes. However, Intel have recently changed the logic to where light AVX workloads will no longer trigger the offset. This change in approach means that only the heavier AVX workloads will downclock the CPU if you use negative offsets. In addition, beginning with Rocket Lake, AVX offsets are now applied to each individual maximum core ratio rather than just applying to the factory All-core Turbo 2.0 ratio. While both these enhancements have the potential to increase the utility of AVX offsets, I still recommend trying to avoid using them if at all possible. It will ultimately make stability testing a little easier.
Step 3: We all start from the perspective that we want our CPUs to run unencumbered. However, CPU temperatures have never been such an issue as they are with Raptor Lake. It’s therefore important to be rather conservative with your CPU’s power limits in order to stay within the capabilities of your particular cooling solution. The goal should be to keep temperatures below 95C for true stress tests (e.g. Prime95, OCCT, y-cruncher, etc.), below 85C for simulation and synthetic benchmarks (e.g. Cinebench R23, Geekbnech, etc.), and below 75C for everything else. Ideally, your gaming temps should average in the 60’s, only spiking into the 70’s during heavy shader compiling that makes heavy usage of all the CPU’s cores and threads. Keeping those high temperatures down can help to reduce the normal rate of silicon degradation and therefore extend the life of your CPU and surrounding components.
Long Duration Power limit(W) >> [PL1] >> See note for PL2.
Long Duration Maintained(s) >> [TAU] >> The time (in seconds) that PL2 power limits will remain in control until PL1 takes over. It's common practice to leave this setting at the default.
Short Duration Power limit(W) >> [PL2] >> While measured in what Intel describes as TDP, you can simply think of this setting as limiting the peak Watts that can be consumed by the CPU.
CPU Current Limit(A) >> [IccMax] >> This setting attempts to limit the "peak" current that can flow through the CPU.
Tip: For help with selecting safe and reasonable limits for your CPU, see the information provided in the following post, including Intel’s latest Raptor Lake guidance. Note that when you select the CPU Cooler preset ”Intel Defaults“, the BIOS should already default to sensible power limits based upon Intel’s guidance.
Tip: These days, the easiest and most common approach to establishing your PL1 and PL2 power limits is to use Cinebench R23. You can often use Cinebench R23 to identify the maximum capabilities of your cooling solution and then use that understanding to set your PL2 value. You would then set your PL1 value equal to or less than PL2 depending upon your risk tolerance. Lower temperatures for long running workloads mean less chance for CPU silicon degradation. To dial in the PL1 value, you should experiment with your normal long-running workload tasks. For example, you could set a lower PL1 value to ensure that your gaming temperatures remain in the 60’s. Many of today’s games only require 150W or less, so this is a good place to start when it comes to setting a lower PL1 than PL2. Incidentally, when it comes to games, long shader compiles can really hammer your CPU. A lower PL1 value versus the PL2 value can help to keep a lid on temperatures during these activities. The same is true for other long running “spiky” workloads, such as video rendering, uncompressing files, etc. For short bursts in workload demand, PL2 will be in effect. The rest of the time, PL1 is in effect. In regards to setting a Current limit (IccMax), see Intel’s recommendations in their chart. For a practical guide on how to establish power limits within the MSI BIOS, refer to step 1 in CiTay's Guide.
Tip: I deliberately placed the tuning of the Power Limits early in the sequence of events for one important reason. If you dial in your undervolting settings by following the Steps 4 - 6 and then change the power limits afterwards, you can run into stability issues. So just be aware that if you increase power limits at a later date, you may have to revisit your CPU Lite Load and/or negative offset voltages to re-stabilize the system, i.e. back them off a little. Keep this in mind.
Step 4a: People often have strong feelings about which Loadline Calibration Control (LLC) setting to use. For less experienced tuners, I recommend just starting out with the Auto setting. The biggest differences come from your choice to use a droopy LLC versus a flatter LLC. It will often depend on how you use your PC. If you are doing a lot of highly multi-threaded activities, such as video rendering, then a more droopy loadline (LLC 6,7,8) is often best. If you predominately play games (typically non-all-core workloads) then a less droopy loadline (LLC 3,4,5,(6=overlap)) combined with a voltage offset via adaptive+offset or V/F points might be best. This is because, with gaming type workloads, PL1, PL2, IccMax and AC_LL are far less active at reining in higher voltages. However, if you can lower the AC_LL value even when using a droopy Loadline and use a negative offset then that's the best of both worlds.
Step 4b: Okay, this is now the least difficult step thanks to step 2 of CiTay's Guide. If you have chosen to keep CEP enabled then you will also want to read Vassil_V's case study guide and his follow-up comment. As you follow these various guides that focus on reducing CPU voltage, you may also find that your CPU can now boost higher in frequency (and therefore performance) while still staying under the power limits that you established in Step 3. If, after lowering your voltage, you find your CPU is running too cool (i.e. your entire PC system has more thermal headroom) then you always have the option to return to Step 3 and slightly increase the power limits you previously chose.
Tip: Before you attempt to read the above guides, you may benefit from reading my next post in this thread [LEVEL 2 knowledge] for background information on the various settings of Intel's voltage control system, which is referred to as the Intel Loadline mechanism. However, it's quite likely that you'll need to revisit this information periodically. In other words, don't try to understand all of it in one reading.
Step 5: A manual voltage offset can have the biggest impact on voltages for non all-core workloads and normal activities, like gaming. The most popular voltage offset is the Adaptive+Offset option. Note that while manual offsets are relatively easy to implement, they usually require extensive, and potentially time-consuming, stability testing. You really won't know for several months whether the CPU voltage and frequency related settings you chose in conjunction with the manual voltage offset are truly stable. Still, the rewards can often outweigh the extra effort of testing and tweaking.
In the above example, the user has selected to implement a negative(-) 110mV offset to the automatic "factory voltage" by using the Adaptive + Offset mode. Be aware that this voltage reduction will apply to all frequencies and all workloads, including your idle voltage. Due to this behavior, what can sometimes happen is that you find your system is perfectly stable under heavy load, but unstable under lighter loads or even at idle. If this situation occurs then you have no choice but to reduce the amount of negative offset even if it means higher voltages under full load. The amount of voltage offset your CPU can handle typically ranges from -10mV to - 150mV, and will ultimately depend upon many variables, including:
>Silicon Quality and luck
>Degradation
>The settings you choose for the Intel Loadline mechanism
>The frequencies and workloads your CPU experiences
>Cooling system capabilities
Tip: If your BIOS does not have the (-) option for CPU Core Voltage Offset Mode then use "- (By CPU)".
Tip: In addition to the usual BSOD, system freeze, application crash, or unexplainable mouse hesitation/stutter (all common signs of CPU voltage issues - usually because it dropped too low) also keep an eye out for WHEA errors in the Windows Event Log (also trackable in HWInfo64). These errors can occur at any time, likely indicating that your CPU voltage settings are not stable under all conditions. In most cases, slightly increasing CPU voltage should fix the problem. But you can also try lowering the power limits if the instability occurs during all-core workloads. For more information, refer to Level 5 Knowledge.
Step 6: This task should be a piece of cake, but instead is made unnecessarily difficult because MSI will neither do it for us (like ASUS), nor will they provide the information we need (i.e. the LLC impedance for each setting 1-8, and Auto) to make it easier to do it for ourselves. Luckily, this is not a mandatory step. Your system will continue to function whether you complete this step or not. A separate guide on how to tune your DC_LL is planned for the future, but in the absence of this guide I would simply advise setting the DC_LL a little higher than the AC_LL when adjusting the AC_LL value.
Step 7: Trying different undervolting and power tuning approaches requires patience and a considerable time commitment. It will also require another emotional decision when it comes to picking the winning configuration.
To recap: We know that undervolting via lowering the Lite Load setting (in Normal mode) or AC_LL (in Advanced mode) greatly benefits voltage, power usage and temperatures for all-core workloads. We also know that undervolting via a negative voltage offset (e.g. Adaptive+Offset) is effective at lowering voltage, power usage and temperatures for all workload types. However, this undervolting method is not usually as effective as the former method when it comes to taming temperatures, etc. for all-core workloads. In addition, proving a large Adaptive Offset as stable can be more challenging than just lowering the AC_LL value because, unlike the Adaptive Offset, the effect that AC_LL has on voltages is inversely proportional to the current (amps), with idle being the least affected. In the real world, this means that Cinebench and Prime95 multi-core tests are greatly affected, while games and MS Office are far less affected. Adaptive Offset is the opposite. It has a statistically greater impact on low current applications than high current applications.
Given our understanding of the behavior of the two most popular methods of undervolting is the reason why it can be a good idea to implement both methods at the same time. I find a good approach is to first find your lowest undervolt via lowering AC_LL then see how much Adaptive Offset you can add on top. Any approach, including this one, requires making decisions about whether you want to keep CEP enabled, and which LLC level you want to start out with - Auto is fine. You can then experiment with different approaches. Sometimes a flatter LLC (e.g. 3 - 6) with a lower AC_LL is more optimal than a droopier LLC (e.g. 7 - 8) and a higher AC_LL. As a general rule, you can usually stabilize a lower AC_LL (with or without CEP enabled) when selecting a flatter LLC setting than a droopier one.
Tip: I always advocate for having a saved OC Profile for when bragging rights are important (e.g. Cinebench R23 high-scores), but having a game-tuned profile for daily use.
Tip: Access our Raptor Lake Survey Settings “database” to see what others have chosen for their settings. And for additional research material, keep reading this thread. Plus, don’t forget to submit your settings to the database when you eventually find that happy equilibrium between temperatures and performance.
Step 8: A CPU VR Voltage Limit is a new MSI BIOS setting that was implemented when the 0x12B microcode was released. If you do not enter a manual voltage limit, the default behind the scenes is set to 1.55V. If you are concerned about high voltages, and you notice that your CPU usually stays below a certain peak voltage (both VID and Vcore), then you are now able to implement a manual voltage limit below the 1.55V default. I think a good general rule of thumb is to add 50mV to the highest peak voltage you have seen during extended monitoring with HWInfo64 (e.g. 1.40V => 1.45V) or use 1.35V. Pick whichever is the highest for your system based upon your monitoring of different activities. If you think you have lost performance in some activities, or can measure it via benchmarks, then add another 25mV. You can see how we went about establishing a VR limit for one forum member in this conversation found here.
In my opinion, Raptor Lake voltages (as observed by HWInfo64 "Vcore") can be categorized as follows:
Voltage peaks above 1.50V = potentially bad for the life of the CPU
Voltage peaks between 1.45V - 1.49V = possibly okay, but still in the historically uncomfortable zone
Voltage peaks between 1.40V - 1.44V = likely okay, but not ideal
Voltage peaks between 1.35V - 1.39V = should be safe
Voltage peaks below 1.35V = very safe (historically) and easier on your cooling solution
Note: Note that the CPU VR Voltage limit will not stop voltage jumps due to momentary transient spikes when the CPU rapidly transitions from high workloads (especially all-core workloads) to very low workloads or idle. When measured on an oscilloscope, these voltage spikes are typically in the neighborhood of +50mV on top of peak voltages seen in HWInfo64. However, transient spikes have been a thing since the early days of CPU development and should not, in theory, meaningfully shorten the life of your CPU - especially if you undervolt your CPU and/or implement a CPU VR Voltage Limit well below the default 1.55V.
I’ve tried to arrange the information in this guide in a way that takes the reader down this rabbit hole we call “undervolting” at a pace that matches their curiosity. At any point along the way, you are free to jump off to the much simpler beginners guide created by CiTay. If you do decide to use CiTay’s guide then I can recommend this example of a before and after case study.
However, if you decide to keep reading then think of the information I present in this guide as both a prelude to Citay’s guide and a “next-steps” knowledge base for those who want (or are curious) to take undervolting to the next level. At a minimum, it might serve as useful reference material once the reader has gained some prior undervolting experience.
[LEVEL ONE KNOWLEDGE]
I've been working on a standardized approach to Raptor Lake voltage tuning. But before I get to that, perhaps we should ask the question "Why do we undervolt?" In the old days, all we talked about was "overclocking." But these days, undervolting is often much more desirable. After all, our PCs are already noisy and hot enough as it is, don't you think?
Reasons to undervolt might include one or more of the following:
[1] Fix a PC with excessive fan noise, especially while running stability tests, benchmarks, heavily multi-threaded applications and playing games.
[2] Increase the longevity of PC components by reducing the kind of degradation that occurs when components get overly hot.
[3] Squeeze every last bit of CPU performance from your PC within the limitations of your existing cooling system.
[4] Less common, but maybe to stabilize an unstable system.
How does silicon quality, referred to as the "silicon lottery," affect your undervolting and overclocking results:
[1] While CPU stability will generally increase with higher voltage levels, a CPU's silicon quality will ultimately have a Core Frequency (Core Ratio) "wall." This means that you will not be able to increase your CPU's core frequency no matter how much voltage you feed it. In some cases, the quality of a single P-Core or E-Core can determine the maximum frequency a CPU can operate at and still remain stable.
[2] When undervolting is the objective, the same frequency-to-voltage relationship will apply. Your CPU's silicon quality will ultimately determine the minimum voltage that each core frequency (Core Ratio) can operate at and still remain stable.
[3] CPU temperature has a direct effect on the minimum voltage your CPU will require in order to remain stable at a given frequency. A CPU's temperature will typically increase in direct relationship to the power consumption (Watts). It is also influenced by the quality of the silicon (i.e. voltage leakage), the ambient temperature of your room, the CPU cooler performance and the case cooling performance.
A quick note: Don't forget that your case cooling performance (in addition to your CPU cooler) can have a direct effect on both CPU temperatures and overall system stability. In particular, cases with solid front panels plus front mounted fans are particularly problematic when it comes to component temperatures. These cases can easily create a "negative pressure" environment, basically where more air is exiting the case than entering the case. Symptoms of a negative pressure condition include unusually high motherboard chipset (e.g. Z690, Z790) temperatures (>65C) and RAM temperatures (>50C).
If you are relatively unaccustomed to this level of BIOS tuning, please don’t worry if the first time you try to follow these steps (as sequenced) you have to keep stepping back. It might take a little prior knowledge and personal experience before you can more easily make these decisions in the order presented. Hindsight is everything. However, if you have any suggestions on how I might improve this guide, which is still a work-in-progress, then please don’t hesitate to leave a comment in this thread. Cheers!
So without further ado, here are the steps that I think make the most sense based upon watching two dozen people struggle with this effort. I've tried to lay out a step-by-step process that (a) provides some important background information for beginners, and (b) side-steps any potential conflicts caused by doing things in the wrong order.
Step 1a: Decide on which CPU Cooler Tuning [preset] to use to configure important BIOS defaults. |
Step 1b: Decide on whether you want to try to tune with Current Excursion Protection (CEP) Enabled [can add more complexity] or Disabled [usually results in less complexity]. |
Step 2a: Decide on which type of workloads are most important to you when it comes to your temperature and voltage tuning. Do you want the lowest possible voltage and temperatures for Prime95 (i.e. highly multi-threaded/all-core workloads) or Battlefield 5 (i.e. single threaded/less than all-core workloads)? |
Step 2b: Decide on whether to retain the stock factory boosting behavior or whether you want to implement manual turbo offsets or manual max-core ratios. You can use this step to either manually “overclock” (to maximize performance) or “underclock“ (to reduce power usage/temperatures) depending upon your priorities. |
Step 3: Select your CPU’s Power Limits (PL1, PL2, IccMax) to match your cooling solution and target temperatures. |
Step 4a: [Optional/Advanced Tuners] Decide on your Loadline Calibration Control (LLC) setting. |
Step 4b: Begin tuning CPU Lite Load [Novice Tuners] or AC_LL [Advanced Tuners]. |
Step 5: [Optional/Advanced Tuners] Add a Manual Voltage Offset. |
Step 6: [Advanced Tuners] Tune DC_LL to fix VID and CPU Package Power inaccuracies. |
Step 7: Save your final settings (after stability testing) to a BIOS OC Profile (1-6) and then repeat steps 1 - 6 making different choices. Compare your different configurations and pick a winner that works best for your normal PC usage. |
Step 8: [Optional] Add a manual CPU VR Voltage Limit to your final choice of settings. |
Background Information
Step 1a: Selecting the best CPU Cooler Tuning preset requires a certain level of knowledge and experience, and in some ways is an emotional decision. For example, do you really trust Intel and MSI to pick the best defaults for your unique CPU and usage case? If you are new to tuning then the answer is probably ”Yes!” However, as you gain more tuning expertise, you will likely want to take more direct and preemptive control over the power, voltage and core frequency settings. Selecting a different CPU Cooler Tuning mode can sometimes simplify things. Luckily, however, regardless of the preset you choose (e.g. Intel Defaults, MSI Performance, MSI Unlimited, etc.), you can usually achieve the same end results by using a slightly different combination of defaults and user-overrides - although Intel may make this more difficult with future CPU generations.
Tip: The CPU Cooler Tuning preset you choose can, and will, alter the defaults for the following settings (still a work-in-progress list):
Long Duration Power limit(W) >> [PL1]
Short Duration Power limit(W) >> [PL2]
CPU Current Limit(A) >> [IccMax]
IA CEP Support
IA CEP Support For 14th Gen
TVB Ratio Clipping >> [All i9 CPUs]
TVB Ratio Clipping Enhanced >> [14th gen i9 CPUs ONLY]
CPU Under Voltage Protection >> [Intel whitepaper]
LoadLine Calibration Control (LLC) >> [Auto** value can change behind the scenes]
CPU Lite Load Control
CPU Lite Load [setting] >> [affects the hidden values AC_LL** and DC_LL**]
** "MSI Unlimited" preset appears to select an Auto LLC value of maybe 5, 6, or 7 and then sets AC_LL and DC_LL to “hopefully” match this LLC level, e.g. AC=50/DC=80.
** "MSI Performance" preset ....???
** "Intel Defaults" preset has consistently selected Auto LLC value of 8 and set AC_LL and DC_LL to “hopefully” match this LLC level, normally AC=110/DC=110 (but sometimes 170/170).
Tip: Don’t worry if the above three ** points make no sense to you. It should make more sense after you finish reading my Level Two Knowledge post in this thread.
Tip: Less experienced Raptor Lake tuners should consider starting out with the Intel Defaults preset because it mirrors most of Intel's recommended guidance, including reasonable power limits for your CPU. However, note that the Intel Defaults preset will likely need some serious manual tuning to bring down potentially high voltage and power usage conditions. That's because it has been configured for maximize stability rather than efficiency. More experienced tuners should consider using one of the MSI presets.
Tip: The latest BIOS releases from MSI will likely enable C1E Support by default. This setting was previously set to disabled. In a related point about C-States, be aware that, in some cases, the Package C State Limit setting, especially in the highest sleep states, can cause instability when the CPU is at idle, presumably because voltage drops too low after your undervolting efforts. If you run into idle instability (but all other activities are stable) then either try changing the above C-State settings to be less impactful or simply back off a little on your undervolt. Keep this point in mind for future reference.
Step 1b: The benefits of Current Excursion Protection (“IA CEP Support”) is an ongoing source of debate. The decision to enable or disable CEP is partly an emotional decision in the absence of more convincing data one way or the other. In general, tuning with CEP is often more difficult than tuning without it. It is therefore an important decision that should be made at the earliest stage in the process. As you continue learning more about the role of CEP (keep reading this thread and the recommended links) you may come to better understand both its importance and how to tune with it enabled.
Tip: Be aware that when selecting CPU Cooler Tuning preset “Intel Defaults“, CEP will normally be enabled by default. But when selecting one of the two MSI presets, CEP might be disabled by default.
Step 2a: Do you want to tune your CPU for highly multi-threaded workloads (such as Video processing, Unzipping files, etc.) or non-all-core workloads - like most game engines. This decision can end up driving you crazy if you are trying to maximize benchmark scores and have good gaming temps. For example, Cinebench R23 loves lots of voltage and sky-high power limits (PL1, PL2 and IccMax) - assuming your cooling solution can keep up. On the other hand, games, web browsing, Microsoft Office tasks, etc. are generally low-power activities and therefore allow for much lower voltage (and power limits) to maximum efficiency and run with the coolest temperatures. In the end, you will undoubtedly have to prioritize one over the other. If bragging rights or highly multi-threaded applications are important to you then consider a separate BIOS OC Profile for just those occasions....then have another OC Profile for all other activities, including gaming.
Step 2b: This is an important decision. Do you want Intel to control all the core boosting behavior in order to maximize light load performance (especially single and dual core workloads) but at the risk of more elevated CPU voltages? Or do you want to implement your own individual CPU core frequencies (including the old fashioned All-core frequency approach), which can help to reduce voltages at the expense of slightly reduced light-load performance, e.g. some gaming workloads? Keep in mind that the highest Voltage request (VID) from all the individual IA Cores (both P-Cores and E-Cores), plus the Ring VID, will always decide the voltage the CPU requests from the motherboard’s VRM power module. Due to the Voltage/Frequency (V/F) curves (one for each IA Core) voltage requests (i.e. VIDs) are directly linked to core frequency. If you ask a particular CPU IA Core to hit a higher frequency, it will often require more voltage to remain stable. The same is true if you increase the Ring Ratio. The amount of additional voltage will ultimately depend upon the quality of the silicon in that part of the CPU Die and the temperature you run it at. Conversely, when you lower the peak frequency of a CPU Core (by using a manual core ratio limit or negative turbo offset) you will usually see a lower peak VID request from that particular IA Core.
See the BIOS configuration example below where one of the manual core ratio options is used to lower the maximum P-Core Ratio to 56 and the maximum E-Core Ratio to 41. Notice that in the factory default configuration, P-Core 4 and 5 are considered the “preferred” cores (i.e. better silicon/less voltage needed) and therefore allowed to boost higher than the other cores.
Tip: When implementing manual core ratios, you are forced to use the ”MSI Unlimited” CPU Cooler Tuning preset. This will likely not bother you if you were already using the other MSI preset called “MSI Performance”. However, if you were using the “Intel Defaults” preset, and this is the preset mode you prefer, then you can try to switch back to the “Intel Defaults” preset after making the core ratio change (or any other change that kicks you out of this preset). Some users report that this trick works. But, either way, make sure to revisit Step 1a/1b before moving on to Step 3.
Tip: Of course, you do have a third choice. You could allow the factory boosting behavior to remain in place (see example below) but control the behavior with Turbo offsets, AVX offsets**, Ring offsets, or by disabling Intel Turbo 3.0 that controls single core and dual core boosting for the preferred cores, which is often responsible for the highest peak CPU voltages. Also, while it’s not generally recommended to disable Thermal Velocity Boost (TVB) [i9’s only] and Enhanced Thermal Velocity Boost (eTVB) [14th gen i9’s only], you can in fact alter the factory TVB behavior with manual settings, referred to as OCTVB. In each one of these cases, you can control CPU voltages by manipulating the maximum frequency a core will automatically boost to via the factory algorithms. Again, higher frequency of any one IA Core usually means higher voltage for the entire CPU. With Raptor Lake’s history for degradation, lower voltage is always safer than higher voltage. [This guide may cover Turbo offsets and OCTVB configurations in the future.]
The above table shows the standard factory frequency boosting technologies for the eight (8) P-Cores inside the 14900K SKU. The bottom axis shows the number of active P-Cores and the side axis shows the core frequency.
Key:
Base is the base frequency if you were to disable Intel Turbo 2.0.
TB2 (Turbo Boost 2.0) is limited by the maximum core frequency (per Intel spec. sheet), the main power limits: PL1, PL2, and TAU (how long PL2 can remain active), plus the CPU Package temperature (TJMax), which usually defaults to 100C.
ABT (Adaptive Boost Technology) was first introduced with Rocket Lake. It is not user-configurable for Raptor Lake.
TB3 (Turbo Boost 3.0) was introduced with Alder Lake and is exclusive to i7 and i9 CPUs. It identifies two “preferred“ cores to boost higher under certain conditions. It’s primary focus is to benefit single-threaded applications/events. While not always the case, TB3 can result in the highest voltages seen for your CPU. You can disable this feature in the BIOS.
TVB (Thermal Velocity Boost) was introduced with Comet Lake and is exclusive to i9 CPUs (regardless of whether it shows up in the BIOS). It can be user-configured via a separate OCTVB BIOS submenu. The default behavior is to opportunistically boost core frequencies whenever CPU temperatures are maintained below ~70C.
eTVB (Enhanced Thermal Velocity Boost) works in conjunction with TVB to boost Core Ratio by +1.
** Tip: In the Comet Lake (and earlier) days, AVX offsets could actually lead to instability due to it constantly cutting in an out and causing transient spikes. However, Intel have recently changed the logic to where light AVX workloads will no longer trigger the offset. This change in approach means that only the heavier AVX workloads will downclock the CPU if you use negative offsets. In addition, beginning with Rocket Lake, AVX offsets are now applied to each individual maximum core ratio rather than just applying to the factory All-core Turbo 2.0 ratio. While both these enhancements have the potential to increase the utility of AVX offsets, I still recommend trying to avoid using them if at all possible. It will ultimately make stability testing a little easier.
Step 3: We all start from the perspective that we want our CPUs to run unencumbered. However, CPU temperatures have never been such an issue as they are with Raptor Lake. It’s therefore important to be rather conservative with your CPU’s power limits in order to stay within the capabilities of your particular cooling solution. The goal should be to keep temperatures below 95C for true stress tests (e.g. Prime95, OCCT, y-cruncher, etc.), below 85C for simulation and synthetic benchmarks (e.g. Cinebench R23, Geekbnech, etc.), and below 75C for everything else. Ideally, your gaming temps should average in the 60’s, only spiking into the 70’s during heavy shader compiling that makes heavy usage of all the CPU’s cores and threads. Keeping those high temperatures down can help to reduce the normal rate of silicon degradation and therefore extend the life of your CPU and surrounding components.
Long Duration Power limit(W) >> [PL1] >> See note for PL2.
Long Duration Maintained(s) >> [TAU] >> The time (in seconds) that PL2 power limits will remain in control until PL1 takes over. It's common practice to leave this setting at the default.
Short Duration Power limit(W) >> [PL2] >> While measured in what Intel describes as TDP, you can simply think of this setting as limiting the peak Watts that can be consumed by the CPU.
CPU Current Limit(A) >> [IccMax] >> This setting attempts to limit the "peak" current that can flow through the CPU.
Tip: For help with selecting safe and reasonable limits for your CPU, see the information provided in the following post, including Intel’s latest Raptor Lake guidance. Note that when you select the CPU Cooler preset ”Intel Defaults“, the BIOS should already default to sensible power limits based upon Intel’s guidance.
Tip: These days, the easiest and most common approach to establishing your PL1 and PL2 power limits is to use Cinebench R23. You can often use Cinebench R23 to identify the maximum capabilities of your cooling solution and then use that understanding to set your PL2 value. You would then set your PL1 value equal to or less than PL2 depending upon your risk tolerance. Lower temperatures for long running workloads mean less chance for CPU silicon degradation. To dial in the PL1 value, you should experiment with your normal long-running workload tasks. For example, you could set a lower PL1 value to ensure that your gaming temperatures remain in the 60’s. Many of today’s games only require 150W or less, so this is a good place to start when it comes to setting a lower PL1 than PL2. Incidentally, when it comes to games, long shader compiles can really hammer your CPU. A lower PL1 value versus the PL2 value can help to keep a lid on temperatures during these activities. The same is true for other long running “spiky” workloads, such as video rendering, uncompressing files, etc. For short bursts in workload demand, PL2 will be in effect. The rest of the time, PL1 is in effect. In regards to setting a Current limit (IccMax), see Intel’s recommendations in their chart. For a practical guide on how to establish power limits within the MSI BIOS, refer to step 1 in CiTay's Guide.
Tip: I deliberately placed the tuning of the Power Limits early in the sequence of events for one important reason. If you dial in your undervolting settings by following the Steps 4 - 6 and then change the power limits afterwards, you can run into stability issues. So just be aware that if you increase power limits at a later date, you may have to revisit your CPU Lite Load and/or negative offset voltages to re-stabilize the system, i.e. back them off a little. Keep this in mind.
Step 4a: People often have strong feelings about which Loadline Calibration Control (LLC) setting to use. For less experienced tuners, I recommend just starting out with the Auto setting. The biggest differences come from your choice to use a droopy LLC versus a flatter LLC. It will often depend on how you use your PC. If you are doing a lot of highly multi-threaded activities, such as video rendering, then a more droopy loadline (LLC 6,7,8) is often best. If you predominately play games (typically non-all-core workloads) then a less droopy loadline (LLC 3,4,5,(6=overlap)) combined with a voltage offset via adaptive+offset or V/F points might be best. This is because, with gaming type workloads, PL1, PL2, IccMax and AC_LL are far less active at reining in higher voltages. However, if you can lower the AC_LL value even when using a droopy Loadline and use a negative offset then that's the best of both worlds.
Step 4b: Okay, this is now the least difficult step thanks to step 2 of CiTay's Guide. If you have chosen to keep CEP enabled then you will also want to read Vassil_V's case study guide and his follow-up comment. As you follow these various guides that focus on reducing CPU voltage, you may also find that your CPU can now boost higher in frequency (and therefore performance) while still staying under the power limits that you established in Step 3. If, after lowering your voltage, you find your CPU is running too cool (i.e. your entire PC system has more thermal headroom) then you always have the option to return to Step 3 and slightly increase the power limits you previously chose.
Tip: Before you attempt to read the above guides, you may benefit from reading my next post in this thread [LEVEL 2 knowledge] for background information on the various settings of Intel's voltage control system, which is referred to as the Intel Loadline mechanism. However, it's quite likely that you'll need to revisit this information periodically. In other words, don't try to understand all of it in one reading.
Step 5: A manual voltage offset can have the biggest impact on voltages for non all-core workloads and normal activities, like gaming. The most popular voltage offset is the Adaptive+Offset option. Note that while manual offsets are relatively easy to implement, they usually require extensive, and potentially time-consuming, stability testing. You really won't know for several months whether the CPU voltage and frequency related settings you chose in conjunction with the manual voltage offset are truly stable. Still, the rewards can often outweigh the extra effort of testing and tweaking.
In the above example, the user has selected to implement a negative(-) 110mV offset to the automatic "factory voltage" by using the Adaptive + Offset mode. Be aware that this voltage reduction will apply to all frequencies and all workloads, including your idle voltage. Due to this behavior, what can sometimes happen is that you find your system is perfectly stable under heavy load, but unstable under lighter loads or even at idle. If this situation occurs then you have no choice but to reduce the amount of negative offset even if it means higher voltages under full load. The amount of voltage offset your CPU can handle typically ranges from -10mV to - 150mV, and will ultimately depend upon many variables, including:
>Silicon Quality and luck
>Degradation
>The settings you choose for the Intel Loadline mechanism
>The frequencies and workloads your CPU experiences
>Cooling system capabilities
Tip: If your BIOS does not have the (-) option for CPU Core Voltage Offset Mode then use "- (By CPU)".
Tip: In addition to the usual BSOD, system freeze, application crash, or unexplainable mouse hesitation/stutter (all common signs of CPU voltage issues - usually because it dropped too low) also keep an eye out for WHEA errors in the Windows Event Log (also trackable in HWInfo64). These errors can occur at any time, likely indicating that your CPU voltage settings are not stable under all conditions. In most cases, slightly increasing CPU voltage should fix the problem. But you can also try lowering the power limits if the instability occurs during all-core workloads. For more information, refer to Level 5 Knowledge.
Custom View Name | Source | Event# | Location |
WHEA Errors | WHEA-Logger | 19 | Windows Log \ System |
Step 6: This task should be a piece of cake, but instead is made unnecessarily difficult because MSI will neither do it for us (like ASUS), nor will they provide the information we need (i.e. the LLC impedance for each setting 1-8, and Auto) to make it easier to do it for ourselves. Luckily, this is not a mandatory step. Your system will continue to function whether you complete this step or not. A separate guide on how to tune your DC_LL is planned for the future, but in the absence of this guide I would simply advise setting the DC_LL a little higher than the AC_LL when adjusting the AC_LL value.
Step 7: Trying different undervolting and power tuning approaches requires patience and a considerable time commitment. It will also require another emotional decision when it comes to picking the winning configuration.
To recap: We know that undervolting via lowering the Lite Load setting (in Normal mode) or AC_LL (in Advanced mode) greatly benefits voltage, power usage and temperatures for all-core workloads. We also know that undervolting via a negative voltage offset (e.g. Adaptive+Offset) is effective at lowering voltage, power usage and temperatures for all workload types. However, this undervolting method is not usually as effective as the former method when it comes to taming temperatures, etc. for all-core workloads. In addition, proving a large Adaptive Offset as stable can be more challenging than just lowering the AC_LL value because, unlike the Adaptive Offset, the effect that AC_LL has on voltages is inversely proportional to the current (amps), with idle being the least affected. In the real world, this means that Cinebench and Prime95 multi-core tests are greatly affected, while games and MS Office are far less affected. Adaptive Offset is the opposite. It has a statistically greater impact on low current applications than high current applications.
Given our understanding of the behavior of the two most popular methods of undervolting is the reason why it can be a good idea to implement both methods at the same time. I find a good approach is to first find your lowest undervolt via lowering AC_LL then see how much Adaptive Offset you can add on top. Any approach, including this one, requires making decisions about whether you want to keep CEP enabled, and which LLC level you want to start out with - Auto is fine. You can then experiment with different approaches. Sometimes a flatter LLC (e.g. 3 - 6) with a lower AC_LL is more optimal than a droopier LLC (e.g. 7 - 8) and a higher AC_LL. As a general rule, you can usually stabilize a lower AC_LL (with or without CEP enabled) when selecting a flatter LLC setting than a droopier one.
Tip: I always advocate for having a saved OC Profile for when bragging rights are important (e.g. Cinebench R23 high-scores), but having a game-tuned profile for daily use.
Tip: Access our Raptor Lake Survey Settings “database” to see what others have chosen for their settings. And for additional research material, keep reading this thread. Plus, don’t forget to submit your settings to the database when you eventually find that happy equilibrium between temperatures and performance.
Step 8: A CPU VR Voltage Limit is a new MSI BIOS setting that was implemented when the 0x12B microcode was released. If you do not enter a manual voltage limit, the default behind the scenes is set to 1.55V. If you are concerned about high voltages, and you notice that your CPU usually stays below a certain peak voltage (both VID and Vcore), then you are now able to implement a manual voltage limit below the 1.55V default. I think a good general rule of thumb is to add 50mV to the highest peak voltage you have seen during extended monitoring with HWInfo64 (e.g. 1.40V => 1.45V) or use 1.35V. Pick whichever is the highest for your system based upon your monitoring of different activities. If you think you have lost performance in some activities, or can measure it via benchmarks, then add another 25mV. You can see how we went about establishing a VR limit for one forum member in this conversation found here.
In my opinion, Raptor Lake voltages (as observed by HWInfo64 "Vcore") can be categorized as follows:
Voltage peaks above 1.50V = potentially bad for the life of the CPU
Voltage peaks between 1.45V - 1.49V = possibly okay, but still in the historically uncomfortable zone
Voltage peaks between 1.40V - 1.44V = likely okay, but not ideal
Voltage peaks between 1.35V - 1.39V = should be safe
Voltage peaks below 1.35V = very safe (historically) and easier on your cooling solution
Note: Note that the CPU VR Voltage limit will not stop voltage jumps due to momentary transient spikes when the CPU rapidly transitions from high workloads (especially all-core workloads) to very low workloads or idle. When measured on an oscilloscope, these voltage spikes are typically in the neighborhood of +50mV on top of peak voltages seen in HWInfo64. However, transient spikes have been a thing since the early days of CPU development and should not, in theory, meaningfully shorten the life of your CPU - especially if you undervolt your CPU and/or implement a CPU VR Voltage Limit well below the default 1.55V.
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