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B660-I: Performance drop with voltage offset/undervolting

Shosiu
Level 8
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.
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95 REPLIES 95

Nice numbers, I cannot set offset lower than -0.040 V, it crashes/freezes at -0.050.
cinebench score with i3-12100 is 8300.
what is your power gain with that undervolt?

mitchX wrote:
Undervolting now works for me on my Strix B660-I and 13600K using the latest BIOS (2212). They added the option to change the microcode to an other version to get rid of all the nonsense Intel did to their CPUs.....


Wow this actualy looks like it worked. Got a cinebench score of 24029 and the cpu didn't use more than 150W. Runs about 13 degrees cooler than my previous "undervolt" of reverting back to an older bios with slightly less insane default voltages. Thank you.

can you post voltages, offsets, other settings and your system params?

andru_nl wrote:
can you post voltages, offsets, other settings and your system params?


same setup and same settings as mitchX, b660-i, 13600K, -0.15 global core and cache voltage. vcore max is 1.243, but it usually sits at 1.217 while running cinebench.
Temps went from peeking at 97c with bios 2012 APE enabled, or hitting 100c instantly with bios 2212, to maxing out at 83c after a 30 min run of cinebench.

mitchX wrote:
Undervolting now works for me on my Strix B660-I and 13600K using the latest BIOS (2212). They added the option to change the microcode to an other version to get rid of all the nonsense Intel did to their CPUs.

First you have to change the microcode from "Current Microcode" to "0x104 Microcode"

97386

Doing this enables you to set an offset to "Global Core SVID Voltage" and "Cache SVID Voltage".

Leave "Actual VRM Core Voltage" on Auto!

97387


Cinebench R23

Single: 2006
Multi: 23700


CPU-Z Bench

Single: 830
Multi: 9800

So pretty much the expected scores for a stock 13600K.

I set the offest to -150 mV because the latest Bios increased the stock voltage even further to around 1.4 Volts. Looks stable to me so far.

This thread over on Techpowerup pushed me in the right direction: https://www.techpowerup.com/forums/threads/colorful-b760i-frozen-wifi-13600kf-the-fivr-display-is-lo...

Should also work with B760-I. You don't have to use Throttlestop, but that's also an option.

Hope this helps someone.


Hello thanks for finding the thread on techpowerup. I can also confirm that with my i5-13600KF it works.
I setup the same undervolt in bios to -0.15V to global and cache. And got these results.
Also I should note that I have Thermalright contact frame.

97455
97456

Shosiu
Level 8
Hi,
Is this option available for all CPUs or only for unlocked ones?
I don't see this or I'm blind...

Can you be specific what option?
And add your cpu to your profile or post the one you have.

Shosiu
Level 8
I have i5 12500, I can't find "Switch Microcode" option in BIOS, as presented by mitchX.

I can't tell you if this option is only available on 13th gen and/or unlocked CPUs. People reported on this option all seem to have a 13600K so far. Are you on the latest BIOS (2212)?

Beware, if you go past version 1620, you can not roll back!

andru_nl wrote:
Nice numbers, I cannot set offset lower than -0.040 V, it crashes/freezes at -0.050.
cinebench score with i3-12100 is 8300.
what is your power gain with that undervolt?


The negative offset value depends on the stock voltage the mainboard sets for your CPU and the voltage your CPU needs to work properly.

I see a descent power consumption drop from 180W to around 145W in CB23. Overall performance is the same.

mitchX wrote:
I can't tell you if this option is only available on 13th gen and/or unlocked CPUs. People reported on this option all seem to have a 13600K so far. Are you on the latest BIOS (2212)?

Beware, if you go past version 1620, you can not roll back!



The negative offset value depends on the stock voltage the mainboard sets for your CPU and the voltage your CPU needs to work properly.

I see a descent power consumption drop from 180W to around 145W in CB23. Overall performance is the same.


Hi! Another 13600K owner here. Thank you so much for your original post. I have just installed the BIOS update and undervolting finally seems to be working. 🙂

It may very well be that this option is only available for 13th Gen CPUs: The ROG STRIX Z790 Series manual says that switching Microcode is only enabled for 0xB0671 CPUs, which seems to be the CPUID of 13th Gen processors.