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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

trihy
Level 9
It need more testing on both sides.

If clock stays at maximum during benchmark, how can the score be lower?

Also leaving everything at stock and setting AC and DC load line to something around 0.80, 0.60 ohms or lower, gives a nice undervolt leaving cpu voltage at auto. At least this didn't trigger any of the bugs from undervolting on my board.

Just keep clear CMOS at hand when trying AC and DC ohms values.

trihy wrote:
It need more testing on both sides.

If clock stays at maximum during benchmark, how can the score be lower?

Also leaving everything at stock and setting AC and DC load line to something around 0.80, 0.60 ohms or lower, gives a nice undervolt leaving cpu voltage at auto. At least this didn't trigger any of the bugs from undervolting on my board.

Just keep clear CMOS at hand when trying AC and DC ohms values.


That sounds like a different method of undervolting than what Shosiu was testing, which sounded like manually lowering vcore rather than AC and DC load line. You're doing this on a B660-M, correct?Â*

Does this method maintain the same level of performance as stock, but would fail to POST or the system becomes unstable if you reduce load line too much?

I'll post about my testing if I buy the B660-I. but I was hoping to confirm that undervolting via some method is possible, and also am waiting to increase the likelihood that I'd receive a board that ships with BIOS version 1620 or newer, as I'll be using an i5-13600K and don't have an Alder Lake CPU on hand at the moment. Â*

Shosiu
Level 8
I'm still wondering: how's that possible, that trihy can undervolt changing only voltage offset and keep same performance, while Asus tech team says that they have same performance drop like I had?
Trihy, what magic you applied on your motherboard?
Now to be serious, it would be good if you share your bios settings (what you changed), so tech team can re-apply the same and compare results.

Regarding AC Loadline, I tried this and lowering the value (something like 0.7 or 0.8), i was also lowering power consumption and performance as well. So this method doesn't work for me.

Hello all

B660-I owner here, 12700K and of course the same problem as you all have: Undervolting through Actual VRM Core Voltage offset results in crash on boot. Even the slightest setting.
Now just tried IA AC load line at 0.5 and 0.6 but this results in a heavy performance loss.

I am disappointed that this board does not undervolt correctly.
I was not aware Intel blocks undervolting through XTU on B660. Is there no way to disable the undervolt protection?

trihy
Level 9
Changing AC and DC loadine ohms can produce a significative voltage drop at load. It doesn't change stock voltage, just drop more when under load. Reducing too much can cause stability problems. Since nobody knows correct values for this settings, also may vary between mb and CPUs, sometimes you can go too low or too high and won't be able to post.

But seems some users tried and had the same problem with performance.

If you loss boost, it's normal to have less performance. With some settings bios disable boost. But if boost still there, there is something else going on.

Crash or freeze when undervolting should be fixed on latest bios.

Tried increasing tdp? Maybe gets bugged. Try to put 250w or something like that.

Boost still worked.
I am running Bios 1620, is 2012 improved? Can someone with B660-I confirm? I think only B660-M has been fixed.

trihy
Level 9
Freeze are fixed for all B660 boards. At least Asus told that.

The performance issue or whatever it is in b660i remains.

Shosiu
Level 8
Eraserhead, please notice, that freezing issue might be related to C-State limit - for me any undervolting with C-State limit set as C10 causes the system freeze.
C10 without undervolting works fine.
Change it maybe to C6, then issue should be gone.

trihy
Level 9
MSI users seems to have similar problems with performance

https://forum-en.msi.com/index.php?threads/msi-b660-tomahawk-ddr4-cpu-core-voltage-offset.372022/

Some said changing load line level helped. I guess default for asus is level 1, you can try others.

Shosiu: Thanks, will try.
Do I need Bios 2012 or is 1620 already the same regarding undervolting?

Trihy: Thanks, will try.