B660-I: Performance drop with voltage offset/undervolting

[Shosiu]

Hi,
This issue has been initially described in another thread but I decided to start a separate one.
I noticed on my B660-I Gaming, that any negative voltage offset causes noticeable negative performance impact.
As the example - results of Cinebench R23 (multithreaded)
stock settings: 12700 points
0.05 voltage offset: 12200 points
0.08 voltage offset: 7100 points.

This issue is not present on other Asus B660 motherboards - it's working properly on B660M Plus.
It doesn't matter if APE is enabled or not - CPU performance is affected.

My CPU is i5 12500.

It would be good, if someone from Asus tech team compares the behavior of those two motherbaords and make a fix for B660-I as currently undervolting on this motherboard doesn't work at all.

Thanks.

[Chs__]

I'm having the same issue on my b660-i on bios 2012, with a 13600k.

AEP enabled, -0.1v offset, clock speeds stay at 5.1Ghz, package power and temps lower substantially as I'd expect, but my cinebench r23 score drops from 24K to 15K
Weirdly enough with AEP disabled, clock speeds drop to 4.9Ghz and package power stays at 181w with a cinebench score of ~23.3K regardless of undervolt setting. Same exact results with -0.1v, no undervolt and a bunch of settings I've tried inbetween.

Hopefully it can be fixed in a bios update.
Also I'm not sure if this is a bios thing or not but XTU says I have undervolting protection enabled, but in the bios it is disabled.

[ecodrumer]

I got same issue with my i5-13600KF.
if I try to undervolt with -0.01V offset then performance drops in cinebench R23 and R20 from 23.5k to 20k or even lower depends on lower voltage i set in bios. I am using the latest bios version 2012.

My current system is:
PSU: CoolerMaster 850V SFX
CPU: i5-13600KF
GPU: XFX RX 7900XTX
RAM: kingston 5200 CL40 DDR5
MB: Asus strix B660-i
OS: W10 pro

[trihy]

New bios was released for some boards. Give it a try.

[Chs__]

trihy wrote:
New bios was released for some boards. Give it a try.

Went from jumping to 90c as soon as I start a cinebench run and leveling off at around 97 to instantly jumping to 100c and clocks lowering to 4.9ghz, score went from 24K to 23.5
Without APE temps are again higher than before and cinebench score is now 22.8K, down from 23.5 on bios 2012.

Performance seems like it still drops when package power drops, but now using a negative voltage offset I had to go all the way to -0.175 to see a decrease in package power, at which point I got a 20.5K score and bluescreened right after. (suprised the run even finished)
I can't say I have a huge amount of experiene in undervolting but that certainly does not feel right.

[trihy]

Users reported up to 50% performance decrease. A 10% can be considered normal and altered by other factors.

This cpu cant handle more than 0.100-0.120v undervolt.

0.175v wont work.

And you need to check for vcore on hwinfo and compare to stock to see if undervolt was applied.

[ecodrumer]

Hey, so I updated new bios and tried again.
I didn't have time today but I will test the offset voltage tomorrow.
For now I tested limiting PL1= PL2 = 65W, 90W, 180W + stock (all set to auto)

I have thermalright contact frame so and I play only games (no heavy CPU apps) so my CPU will not hit 100%.
But the end result of PL1= PL2 = 180W is awesome. Losing 900 points in benchmark while hitting 87 °C max.
So if someone is using this cpu for rendering I would go for 180W PL. For gaming keep it at stock for the higher P-core clock.

https://imgur.com/a/fo0uW5h

My setup and case I tested in it:
https://pcpartpicker.com/b/z8ZZxr

[happymachi]

New BIOS didn't fix it for me. Pretty disappointing. Thank god I'm still in the 30-day return period.

[excelsior00]

Can confirm, any undervolt on this board will result in severely degraded performance. My 13500 on this board will consume 150-155W on load with high temps >80'C, Cinebench R23 Multi ~21000
With other B660 ITX board from other brand (B660GTN), I can undervolt it with -0.115v offset, and get 115W on load with the same ~21000 CB R23 Multi score, temperature was in the low 60s.

It seems like when the Asus B660I undervolted, something 'interrupts' the CPU under heavy load, so it is still showing full 4.5GHz all core, but it is not working as it should. CB score dropped from 21k to 13-15k. The voltage didn't really change either.

Latest 2212 BIOS + ME Update didn't fix anything.

Please fix it, undervolting is extremely important for any experienced ITX builder.

[ecodrumer]

excelsior00 wrote:
Can confirm, any undervolt on this board will result in severely degraded performance. My 13500 on this board will consume 150-155W on load with high temps >80'C, Cinebench R23 Multi ~21000
With other B660 ITX board from other brand (B660GTN), I can undervolt it with -0.115v offset, and get 115W on load with the same ~21000 CB R23 Multi score, temperature was in the low 60s.

It seems like when the Asus B660I undervolted, something 'interrupts' the CPU under heavy load, so it is still showing full 4.5GHz all core, but it is not working as it should. CB score dropped from 21k to 13-15k. The voltage didn't really change either.

Please fix it, undervolting is extremely important for any experienced ITX builder.

I would also to have it fixed. New bios didn't fixed it even with new Intel ME update.
For now I am gaming so I don't mind having CPU jump to 80C and keeping it most of the time at 74-78C.
Still it is little bit power hungry and would love to have option to have lower power, temps and keep the performance at the same time.

[wcs531]

Add another one to the list. It seems like there is a sharp drop in performance at a random threshold rather than a somewhat linear drop. Just wanted to share some of the things i've tried - most of this stuff is over my head but trying different things I've read in various places to keep my CPU from cooking itself.

Board: Asus ROG STRIX B660-I with Bios version 2212 and Intel ME version 16.1.25.2020V2
CPU: 13600k (with Thermalright contact frame)
Cooler: Noctua U12A
Memory: DDR5 6000
Testing done in NR200 with side panel removed.

Stock would get mid to high 23k on Cinebench R23 and hit 100 degrees almost immediately. Even gaming would get 90+. Repasted and reseated cooler with similar results.

Undervolting with set voltage seemed to return around 15k regardless of voltage requested (I didnt write down the numbers but I was aiming for around the same as the voltage offset).

Voltage offset seems to work OK - I was able to get -0.15 to run through cinebench R23 keeping 22k+ score and sub 100 temps. I didn't bother further testing stability since I was still tinkering and started reading about AC Load Line tweaking.


I read elsewhere that AC Load Line tweaking is the best way to undervolt 12th/13th gen, but there don't seem to be many results with Asus boards.

In my case an IA AC Load Line of 0.5 and below saw a sizeable drop in performance like around 16k I think.

I just ran "IA AC Load Line" at 0.55 with LLC set to level 4 and got 23.2k score in Cinebench R23. Temps jumped to high 80s immediately and slowly crept up to 97 "Core Max" after a ten minute run. Max Vcore under the motherboard in HWInfo was 1.35v. Max temp playing games for a short period was 71C. I am MUCH happier with this result over stock but I haven't really stability tested it and im sure there are better results to be found.