Undervolting and MSI BIOS settings

[lopez.pos155702d9]

I'm aiming to avoid thermal throttling (100C) on a z790 carbon using 13900K cpu. MSI BIOS is set at no power limits, which is contributing to some issues.
Helpful background (if you're not already aware) here:

Intel Core i9 13900K: Impact of MultiCore Enhancement (MCE) and Long Power Duration Limits on Thermals and Content Creation Performance

Intel's 13th Gen processors bring terrific performance across the board, but many modern processors have been criticized for their high power draw and heat output. However, we have found that most CPUs only operate at these high temperatures when the motherboard BIOS is allowed to automatically...

www.pugetsystems.com

and here:

Intel Core i9-13900K Power Scaling Performance Explored - PC Perspective

Intel Core i9-13900K Power Scaling Performance Explored (This is a supplement to our initial Intel Core i9-13900K review.)

pcper.com

I changed the MSI BIOS option "CPU Cooler Tuning" from Water ("PL1: 4096W") to "Boxed Cooler: PL1: 253W." That caused Intel's XTU (Extreme Tuning Utility) to show "Turbo Boost Power Max" and "Turbo Boost Short Power Max" as 253W. However, it looks like 253W is the Intel spec only for PL2 (on 137000/13900K): "Short Duration Package Power Limit" (--prob. corresponds to XTU's "Turbo Boost Short Power Max"). The other setting, PL1 or "Long Duration Package Power Limit" should be at 125W (and probably corresponds to XTU's "Turbo Boost Power Max").

There is an MSI BIOS Option, now set to Auto, called "Long Duration Power Limit" -- should I manually type in 125? And even though unnecessary, manually type in "253" into "Short Duration Power Limit"?

There is also an "Enhanced Turbo" option (now set to "Auto"). I believe that corresponds to Multi-Core Enhancement (MCE) --is that right? so I should set it to disabled (to help prevent temperature throttling at high loads).

What is the best way to undervolt? I've reached a negative 0.095 core voltage offset that's stable, and it may I could go lower and still be stable. But I wonder whether I should also add negative offsets to other voltage offsets (such as cache, or sys agent). Or is the best procedure to keep on pushing core voltage down until I fail a stress test?

 

[coleman60412eb02b5]

Following. Seem to be a thermal animal “stock” on my z790-p ddr4

 

[citay]

Yes, the 13900K is their usual crazy top model, or to quote a review, a "Power-Hungry Beast". This means, to reach the frequencies that it does in a stable manner (and on every board), a very aggressive voltage-per-frequency curve was necessary. On a budget board model, it can also overwhelm the CPU VRM and lead to VRM-induced throttling. Why have Intel chosen such an aggressive approach on the top part once again? In order to have slightly longer bars in benchmarks compared to the Ryzen 9 7950X.

So, undervolting and/or setting custom power limits is definitely the way to go to tame this beast. Often times there is no other choice, because even high-end AIOs are unable to remove that amount of heat from the tiny CPU surface in a timely enough manner to prevent hotspots and generally too high temperatures.

To set the power limits, yes, you would directly punch in the numbers in the Short/Long Duration PL fields.
Read here and follow the links, https://forum-en.msi.com/index.php?...ons-such-as-usb-locks-up.381362/#post-2162073

Undervolting can be done several ways, in the past i have done it with Adaptive mode and a negative offset. Getting to a lower VCore is by far the most important one, the other voltages are less important. Any CPU will request a higher VCore than it really needs, because it needs to work on all kinds of boards, even those with a "suboptimal" VRM. So Intel accounts for subpar VRMs on the boards, but the Z790 Carbon has a good VRM, so you can shave off quite some VCore. Of course, the VCore will still be very high in comparison to lesser CPU models, because they pushed the top-end CPU so far again, so it behaves like a factory-overclocked CPU (in performance, power draw and heat). In my opinion, the i7 models of the current and the last few generations have been the more well-rounded ones. The top i9 has always been like "how can we beat AMD by any means necessary, efficiency be damned".

 

[Billy from Consett]

I'm about to update my 6 year old rig I use for film editing with Adobe Premiere. So an i9 13900k /14900k cpu with a Carbon looks like the best option. I’ll get a decent liquid cooler for this build.
So a guide of undervolting settings from other z790 Carbon users would be most beneficial to reduce power drain and excessive cpu heat.

 

[citay]

See here. It's a process of finding which power limits to set (according to the capabilities of your cooling), and then undervolt using "CPU Lite Load" (or you can reverse the order). Most people with an i9 will probably have to set power limits because of the excessive power draw when running unlimited, which can overwhelm even some powerful AIOs. Then for undervolting, on MSI boards, CPU Lite Load is the best method. It doesn't depend on the board, it depends on the CPU how far you can lower it. But it's the only setting you need to modify to get good results, with often significantly lower power draw and temperatures as a result. Theoretically you could also undervolt the "conventional way" by modifying VCore yourself, but CPU Lite Load will do everything for you, just lower the mode gradually and test for stability. So that's why i recommend that option.