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Does anyone know how to control avx current?

feedmeink
Level 12
As the title states. Does anyone know how to control the current being fed for avx functions? I am having to set my avx offset too low. I would prefer to keep around my current clock speed. I have x299 i9 7980xe custom waterloop. Everything dialed in great, but my avx offset is set to 5 and 7. It is a modest oc of 4.1ghz and I've seen people with non delid chips running at 1 or 2. I run low voltage as well and offset each core to run 1.02 volts at full load. With avx offset set it down volts to .87-.92 volts.
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6 REPLIES 6

metadist
Level 9
I don't think you can control AVX current specifically, but here is what helps me to keep AVX load under control. Since, as you mentioned, AVX load draw substantially more, the power a CPU consumes also increases. Now, you can control the total power cap under CPU Power Management menu item. Set Long duration power Limit to some number that is above your normal full load and less then AVX full load. Then CPU will be told to jump to a lower P-state to conform to this power cap.
In my case, this is 150 and then AVX heavy benchmarks make the CPU drop from 5.1 to some 4.5-4.6 and I see the power stays quasy-constant at 150W
But I have way higher voltages then you, so you should really select your own cap value.

metadist wrote:
I don't think you can control AVX current specifically, but here is what helps me to keep AVX load under control. Since, as you mentioned, AVX load draw substantially more, the power a CPU consumes also increases. Now, you can control the total power cap under CPU Power Management menu item. Set Long duration power Limit to some number that is above your normal full load and less then AVX full load. Then CPU will be told to jump to a lower P-state to conform to this power cap.
In my case, this is 150 and then AVX heavy benchmarks make the CPU drop from 5.1 to some 4.5-4.6 and I see the power stays quasy-constant at 150W
But I have way higher voltages then you, so you should really select your own cap value.





Thanks for the response! Are you referring to power limit of the psu? Or is this in relation to strictly cpu? If I understand you correctly, I would monitor my power draw running stress tests with and without avx function enabled and take note of the power draw? Then pick a sweet spot between the two? As a side note, I did take the chip to 4.6ghz (I am not delided) and found my cinebench scores actually improved by fine tuning each core at a lower clock speed. So I just picked 4.1 and ran with it.

Yuo can limit the power drawn by the CPU in the BIOS, under IA Tweaker/CPU power Management/ Long Duration power limit.
I believe monitoring SW can show what power does CPU draw. It's only applied to the CPU itselt, not the total power usage of the system.

There is also a setting to tune the current limit: "CPU core/cache current limit", but I didn't play with that.

When you fine tune your core clocks to lower frequencies, you might be preventing thermal throttling, and this is indeed a good thing and can improve the csore, since frequency flip-flop is not efficient.

Artem.

As specified, adjust the long and short duration power limits manually if wanting to cap TDP

Current Capacity will limit the power draw, however, if tripped the system will restart.
13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090

Didn't know this was a double post. I'm new here. I'll take care of it this weekend and update if anyones interested. Working 14 hour days the rest of the week.

Silent_Scone
Super Moderator
double post
13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090