Where is the IA CEP option in the bios?

[ke157002db]

Just setup a new MSI MPG B760I Edge Wifi DDR4 + 13900KF. I'm trying to undervolt the CPU. If I select a lower CPU Lite Load mode (mode 9 -> mode 5), the CPU performance decreases according to benchmarks.

I've read that the IA CEP is often the culprit and have seen screenshots from other MSI boards on how to turn it off (Advanced CPU options). However, I don't see the option on my brand new board. Should I update the bios version?

 

[citay]

Updating the BIOS is always a good idea with such a new board (meaning, it has an immature BIOS and there are often important fixes in the first couple BIOS updates).

However, it seems that the B660/B760 in general do not allow undervolting without also incurring a performance penalty from IA CEP (Current Excursion Protection) at the same time. This is what plutomate had already posted here, which comes from this video by TOPPC (MSI in-house overclocker).

Here i made some better versions of the slides from the video:

So for the -KF CPU models, they will only offer IA CEP to be disabled on the Z-series chipset boards. On the B-series there seems to be no way to disable it anymore and prevent the performance drop. So once you undervolt, the performance will also decrease, from IA CEP intervening.

Another "funny" thing is on this slide:

They cannot recommend any off-the-shelf cooling for i9, because it's just so power-hungry. So they recommend a custom loop water cooler.

 

[ke157002db]

Thank you @citay for the (unfortunate) information!

 

[alex_007]

hi all.

intel 13500 + b760 combo undervolting ?

Based on the screen "cpu lower power combination"
intel 13500 + msi b760-p
intel 13500 + msi B760M MORTAR
intel 3500 + MSI MAG B760 Tomahawk

The undervolting adaptive+offset / cpu lite load / power limit
will be aviable without performance drop ?

thanks

 

[citay]

Correct, with the 13500, undervolting without losing performance should be possible, both on Z790 and B760.

By the way, here you see what happens if IA CEP intervenes: https://forum-en.msi.com/index.php?...rd-and-13600kf-processor.384070/#post-2178096

 

[alex_007]

hi, with the msi b760 mean that the IA CEP is disabled by default ? Is there the option turn on/off the IA CEP ?

thanks

 

[Alan J T]

hi, with the msi b760 mean that the IA CEP is disabled by default ? Is there the option turn on/off the IA CEP ?

thanks

Yep will be an Intel default setting one MSI can not override

 

[alex_007]

Ok, it's a good news if the ia cep is disabled by default in the b760, so you can undervolting 13500 without performance decrease

 

[alex_007]

hi, Are there any owner that can confirm if the undervolting is aviable with msi b760 + i5-13500 ?

 

[citay]

Additional information from my own new system, Z690 TOMAHAWK WIFI DDR4 + i5-13500. I updated the BIOS first using the Flash BIOS Button.

No option "IA CEP Support" available in the latest BIOS, but just as MSI's table shows, i can undervolt the CPU without losing any performance, so IA CEP doesn't intervene.
I am undervolting using CPU Lite Load, see here on how to do that.

The other settings on this page are also important. Set "Package C State Limit" to C10 instead of Auto. When setting it to C10, the CPU will enter C7 state in idle, instead of only C6. The C7 state lowers power consumption in idle by around 6W for me (37W -> 31W).

Results:
CPU Lite Load Mode 12 (default) - CB23 score: 20962 - total system power draw: 182W, CPU only: 135W (HWinfo64 CPU package power).
CPU Lite Load Mode 1 (crashes in Prime95 Small FFTs!) - CB23 score: 20935 - total system power draw: 141 W, CPU only: 105W.
CPU Lite Load Mode 4 (stable so far) - CB23 score: 20955 - total system power draw: 149 W, CPU only: 114W.

The CB scores are all within the margin of error, basically identical. They only drop by ~300 points when i also monitor the sensors with HWinfo64 in the background.

 

[alex_007]

@citay
hi, i have build b760 tomahawk + i5-13500 + 16GB ram ddr4 3200MHz, i leave the pl1=pl2 = 4095W
i have made some test with cpu lite mode 4,2,1. ..... the mobo handle the lite mode 1 but lose a few points in cinebench 23 multy score ... so i'm stick with cpu lite load 2, the temp drop from 70°C to 60°C in full

cpu lite load 2 result
score | cpu package temp | cpu package power
multy 20856 / 60°max / 109,220W
single 1858 / 45°max / 34,545W

multy 20890 / 60°max / 109,667W
single 1850 / 46°max / 33,096W

multy 20904 / 60°C / 110,019W
single 1849 / 44°C / 35,486W

Should i set Set "Package C State Limit" to C10 instead of Auto for better efficiency ?

thanks

 

[citay]

Nice one. Have you also taken baseline numbers for comparison, with the default CPU Lite Load mode?
What's your CPU cooler?

Should i set Set "Package C State Limit" to C10 instead of Auto for better efficiency ?

Yes. Has no downsides, but will have less power draw in idle.

 

[alex_007]

hi,
my first run with cb23 and stock cpu lite load (12), STOCK PL = 4095.9 W
multy 20895 / 70°max / 138,853W
single 1830

i use air cpu cooler, noctua nh-u12s.

 

[citay]

Looks all pretty similar to me. And yeah, around 110W you seem to have some stability with this CPU model.
I have a Noctua NH-D15, total overkill for this CPU, but it allows me to keep a very quiet system even under full load.

 

[alex_007]

yeah i'm very happy for now how can i inprove the cpu efficienty without significative performance drop

How can i check the idle state cpu power usage ? just leave the pc in idle for a bit time ?
I would like test before and after C10 state bios tweak ....

 

[citay]

How can i check the idle state cpu power usage ? just leave the pc in idle for a bit time ?

Yes, just leave it in idle. If Windows has just loaded, it will usually do stuff off and on for maybe two minutes, only after that can you get reliable idle numbers. I checked it with an energy meter at the power socket, i saw a 6W reduction there. But you should also see a drop for CPU Package Power in HWinfo, plus it should show that it then enters C7 state and not only C6.

 

[alex_007]

@citay
hi, after i activate "Package C State Limit" to C10, the C7 state come up in the hwinfo64.

how i tested:
i opened hwinfo for 5 minutes with C auto and C10 to see the difference.
C auto -> cpu package 10,203W max
C10 -> cpu package about 5-6W max, after 5 minutes the cpu package power start using a bit more power(W)

Is the normal behavior ?

thanks

 

[citay]

Yep. Instead of C6, you enter the deeper C-state C7, so the CPU needs even less power in idle. About it using more power after some time, that's just Windows doing some background tasks. The minimum number is more important, in C6 you will never see as low a number as in C7.

 

[shakedown1986]

The C10 state causes the system to freeze when the Windows Power plan Set to Power saver

 

[citay]

Which board do you have?

But yes, in certain edge cases, "Package C State Limit" on Auto may be necessary to prevent weird issues. But those are very rare, usually it works completely fine when set to C10. As for the power plan, i would just use Balanced, there is rarely any reason to use anything else. In Balanced, you can already make the CPU power draw in idle as low as it could ever be, if the BIOS is set up correctly.

Under "Advanced CPU Configuration" in the BIOS, i always tend to set the following:
"Intel C-State" to Enabled (Auto should equal Enabled)
"C1E Support" to Enabled (clocks down in idle)
"Package C-State Limit" to C10
"Intel Speed Shift Technology" to Enabled

Then under Settings\Advanced\Power, ErP Ready to Enabled. Reduces power consumption in off state to less than 1W instead of 2-3W.

Under Settings\Boot, set both Fast Boot options to Disabled (Fast Boot is not good for much and is sometimes problematic).

Then we have the Active State Power Management modes, Auto should default either to L0s only or maybe to L0s+L1.
The best would be to select L0sL1 (where available) or L1 manually, this means maximum energy saving.

The energy reports under "C:\ProgramData\Microsoft\Windows\Power Efficiency Diagnostics" will show if the power savings actually get applied or not. This will have an impact on an M.2 PCIe SSD's power consumption for example. L1 is a really low-power idle state and it can save as much as 2W per M.2 PCIe SSD.

Sometimes this can have a negative effect on a graphics card, they may not like those power-saving modes. Then set PEG 0/1 ASPM back to Auto.

With these settings in place, then the one thing i also tend to do is to set PCIe Link State Management to Maximum Power Savings in the Balanced power plan:

This will make sure the PCIe devices like M.2 SSDs actually enter the L1 power-saving state. There is only a slightly higher exit latency coming out of L1 state, nothing you could feel. But the power savings are there all the time. Set up like this, the "Balanced" power plan is by far the best one, as it will not also restrict your performance in any way.