Advice for undervolting (13600K)

[homerdog]

Anyone have any tips for undervolting a modern Intel CPU? I want to keep stock clocks and lower power/temps. I don't have a watercooler (seen first hand what happens when they leak) and my Deepcool AK400 is just shy of being able to maintain 5.1GHz under max load.

I have a 13600K and Gigabyte Z790 UD AC. I went into the UEFI and set voltage offset to Legacy mode and then went -0.025V on the core and -0.025V on the ring. This did drop package power and temps a bit but I'm not sure if there's a better way or how low I'm likely to be able to go on a setup like this.

 

[T2098]

Anyone have any tips for undervolting a modern Intel CPU? I want to keep stock clocks and lower power/temps. I don't have a watercooler (seen first hand what happens when they leak) and my Deepcool AK400 is just shy of being able to maintain 5.1GHz under max load.

I have a 13600K and Gigabyte Z790 UD AC. I went into the UEFI and set voltage offset to Legacy mode and then went -0.025V on the core and -0.025V on the ring. This did drop package power and temps a bit but I'm not sure if there's a better way or how low I'm likely to be able to go on a setup like this.

I wish I hadn't lost my notes from when I dialed in my 13600k when I first got it. I do remember that dropping the SOC/IO voltages from the insanely high ones the MB defaulted to was a big win at idle, where my chip spends most of its time anyway.

I also remember y-cruncher being crucial to dialing in the undervolt and memory timings, as lots of other stress tests made it look like it was stable, even for 24hrs, but it couldn't even run y-cruncher for 5 minutes without failing:

y-cruncher - A Multi-Threaded Pi Program

'y-cruncher stress -D:60 FFT VST N32' was my quick first pass test, I'd leave it for 5-10 mins.
'y-cruncher stress -D:60 BKT BBP SFT FFT N32 N64 HNT VST C17' was what got left running overnight for 24hrs when I thought I'd found actually stable settings.

 

[homerdog]

I wish I hadn't lost my notes from when I dialed in my 13600k when I first got it. I do remember that dropping the SOC/IO voltages from the insanely high ones the MB defaulted to was a big win at idle, where my chip spends most of its time anyway.

I also remember y-cruncher being crucial to dialing in the undervolt and memory timings, as lots of other stress tests made it look like it was stable, even for 24hrs, but it couldn't even run y-cruncher for 5 minutes without failing:

y-cruncher - A Multi-Threaded Pi Program

'y-cruncher stress -D:60 FFT VST N32' was my quick first pass test, I'd leave it for 5-10 mins.
'y-cruncher stress -D:60 BKT BBP SFT FFT N32 N64 HNT VST C17' was what got left running overnight for 24hrs when I thought I'd found actually stable settings.

Ima try this right now. Do you recall at all what voltages or offsets you settled on?

 

[T2098]

Ima try this right now. Do you recall at all what voltages or offsets you settled on?

Just checked, I settled on -0.050v for Vcore, with stock clocks. I'd had it down below -0.100v (-0.135v if memory serves?) and it seemed stable in prime95 and Cinebench overnight, but not with y-cruncher, so had to dial it back.

I have two BIOS profiles, and I'm -0.10v for VCCSA in there too for daily use, running the DDR5-5600 kit at JEDEC timings, and then I have a second profile that requires +0.10v for VCCSA for stability at DDR5-6200 with tightened timings for things like Starfield.

I think that works out to 0.95v and 1.15v VCCSA for each on my board, although what the absolute voltages are apparently vary wildly from board to board and even UEFI revision to UEFI revision:

https://www.reddit.com/r/overclocking/comments/11dp2zc

 

[homerdog]

Just checked, I settled on -0.050v for Vcore, with stock clocks. I'd had it down below -0.100v (-0.135v if memory serves?) and it seemed stable in prime95 and Cinebench overnight, but not with y-cruncher, so had to dial it back.

I have two BIOS profiles, and I'm -0.10v for VCCSA in there too for daily use, running the DDR5-5600 kit at JEDEC timings, and then I have a second profile that requires +0.10v for VCCSA for stability at DDR5-6200 with tightened timings for things like Starfield.

I think that works out to 0.95v and 1.15v VCCSA for each on my board, although what the absolute voltages are apparently vary wildly from board to board and even UEFI revision to UEFI revision:

https://www.reddit.com/r/overclocking/comments/11dp2zc

Thanks!

With Y-Cruncher is it necessary to change the group policy in Windows to allow it to lock pages in RAM so they don't get swapped? I don't know the ramifications (security or performance or stability) this would have but the documentation suggests doing that.

BTW I have 32GB (2x16) of DDR5-5600 (XMP).

 

[T2098]

Thanks!

With Y-Cruncher is it necessary to change the group policy in Windows to allow it to lock pages in RAM so they don't get swapped? I don't know the ramifications (security or performance or stability) this would have but the documentation suggests doing that.

You're welcome!

I never bothered myself, and it found the instability real fast regardless.
Bonus graph showing what each test does; your CPU frequency and power consumption should fluctuate a fair bit from test to test.

 

[homerdog]

You're welcome!

I never bothered myself, and it found the instability real fast regardless.
Bonus graph showing what each test does; your CPU frequency and power consumption should fluctuate a fair bit from test to test.

View attachment 11380

Sorry for pestering you but where do I put those commands? It isn't clear from the documentation exactly what file they go in or where in the file they go. Pretty sure it's in there and I missed it . Or maybe they can only be run from the CLI, but it didn't seem to do anything when I tried that because I didn't know which option to choose initially (Benchmark Pi, Component Stress Tester, Run I/O Performance Analysis , etc.).

 

[T2098]

Sorry for pestering you but where do I put those commands? It isn't clear from the documentation exactly what file they go in or where in the file they go. Pretty sure it's in there and I missed it . Or maybe they can only be run from the CLI, but it didn't seem to do anything when I tried that because I didn't know which option to choose initially (Benchmark Pi, Component Stress Tester, Run I/O Performance Analysis , etc.).

Those are just to run it in automatic mode from the command line, I made batch files for each, like below, but you should be able to just paste the text into the command line when you're in the directory you extracted y-cruncher into, and have it do the same thing. If it's working right, simply running the batch file or pasting the command into command prompt should have the test start immediately, no user interaction needed.