Troubles with the AVX Negative Offset

[Wolfdale]

Hello guys, I have the Strix z370-F board and I need a bit of help regarding the AVX Negative offset option.

I'm able to pass a 6-hours-long Handbrake encoding on a 8K video by using the h.265 encoder (AVX enabled). The voltage set is 1.30v (on Manual, not Adaptive or Offset) and the CPU frequency is 5000MHz. LLC-7.

However if I try to run the same test (same 8K video, same encoder, same everything) at 1.29v but with using AVX negative offset "1" (reducing the frequency to 4900MHz) the system crashes in about an hour or so. I have tried "AVX negative offset" 2 and 3 (gearing down to 4800MHz and 4700MHz respectively) but the system is again unstable at 1.29v. Sometimes it just freezes, sometimes there's a BSOD, sometimes the Handbrake encoder just crashes gracefully with a Windows error message. Obviously if 5000MHz at 1.30v is stable, 4900MHz at 1.29v (or even 4800MHz at 1.29v) should also be stable. However for some reason it seems that even that the AVX negative offset gears down the frequency, the voltage needed to maintain stability remains the same as the one needed for 5000MHz. That kind of makes the AVX negative offset useless. Can someone here at ASUS take a look at this behavior and maybe attempt a fix or something?

TL;DR
5000MHz AVX offset 0 @ 1.30v - stable
5000MHz AVX offset 1 @ 1.29v - unstable
5000MHz AVX offset 2 @ 1.29v - unstable
5000MHz AVX offset 3 @ 1.29v - unstable

So AVX offset isn't wokring good enough as I still need the same voltage as the one needed for AVX offset 0.

[Duckysaysquack]

Wolfdale wrote:
Okay, Raja, I finally managed to get my system running the way I want. I had to increase CPU current capability to 140% and set Power Phase Control and Power Duty Control both to 'Extreme'. I switched to LLC-6 with manually setting Vcore to 1.33 in UEFI. X50 multi selected for non-AVX target multiplier, AVX Negative Offset set to '1' too. Got my system perfectly stable. AVX-Enabled LinX 0.7 is kicking happily at 4900MHz producing ~ 385GFlops. My AVX-enabled 8K h.265 video encoding test seems to also be running smooth as silk at 4900MHz and completed successfully in about 6 hours.


Click the image for larger view^^

Those chips are insanely good once put on custom water cooling and de-lidded. 😮
Thanks for all the help, I guess we can close the thread.

I have the same issue with 9700k and Strixx z390. Any AVX offset seems to crash. I've tried your solution with current capability to 140% and even higher with power phase control and duty control to extreme and increase the voltage. Still crashes in prime with AVX disabled.

[Falkentyne]

Duckysaysquack wrote:
I have the same issue with 9700k and Strixx z390. Any AVX offset seems to crash. I've tried your solution with current capability to 140% and even higher with power phase control and duty control to extreme and increase the voltage. Still crashes in prime with AVX disabled.

Lower (steepen) your LLC (more vdroop) and increase the cpu voltage in the bios to compensate, so you get the same overall load voltage as before (yes, the same load voltage you had on the "unstable" settings), then re-test. Go as low as LLC5 is necessary (with this low of LLC, you can safely use up to a 1.40v bios voltage as even idle will be lower than this thanks to vdroop), then find (and post the results here) if the exact LLC, bios idle voltage, and true load voltage you need to be stable, and then post the "same" bios voltage and load voltage and LLC you used on your "orignial" unstable settings, so other users can read and replicate and understand what's going on.

I'm willing to bet that the lower your LLC and higher your bios voltage, the more stable you're going to be at the same load as before (why? Because lower LLC=better transient response).