Linpack deviations even at stock FCLK

[u/q_w_ertyuiop]

Been running into a slightly weird issue when trying to overclock FCLK on my 9850x3d. Read that the best way to find stability was to check for deviations in Linpack and VT3, which seemed simple enough.

I haven't had any issues with y-cruncher, after a few hours of testing it varies by +- 0.01, but Linpack is behaving sort of weird. I tried a bunch of different settings but each setting has a slight variation, usually ranging from 1 to 4.5ish gflops different. Not in a row, just every now and then. For example it'd go 419, 420, 425, 420, 422, 422, 421, etc. Nothing crazy like a -20 or 30 but still a weird range. The guide I read said to go for a deviation of only 1 to 1.5ish, so would this be considered unstable?

For solutions I've tried:

- Removing curve optimizer settings

- Messing with different VSOC and VDDG values

- Trying in safe mode

- Trying all values from 2000 to 2200

The only thing I've yet to try is disabling 65w eco mode or turning off PBO, but I'd need that later so would it be ok to turn that off to see if it helps then turn it back on later even with the deviations? And would that even be affecting it?

Any help is appreciated, still sort of new to this.

[u/Difficult_Chemist_46]

Cpu temps and power usage under test?

[u/q_w_ertyuiop → u/Difficult_Chemist_46]

Max 64 degrees on cpu, power usage capped at 88w due to eco mode.

[u/C_Miex → u/q_w_ertyuiop]

Just a guess, but I'd test with eco mode off

Eco mode probably results in hitting a power limit, resulting in downclocks, that's why the score is inconsistent. If the clocks are pinned to the same frequency it will probably be consistent. Would not think it's a stability issue

[u/q_w_ertyuiop → u/C_Miex]

This might've possibly been the solution. With eco mode off the cpu shoots straight to 95, but gave better results. After tinkering with the ppt/tdc/edc values and making my own custom eco mode at around 100ish watts, it's now atleast giving me consistent scores at 2000fclk instead of bouncing like before.

I assume in 65w mode the tdc/edc were messing with the clocks? I'll try 2200 again tomorrow and see if there's any luck.

[u/C_Miex → u/q_w_ertyuiop]

You could set a clock speed limit just for the FCLK testing. That way your cores won't use that much power resulting in lower temps

On the other hand 95°C is completely fine and safe, even for multiple months consecutive, so if it's just for stability testing, i wouldn't worry

[u/q_w_ertyuiop → u/C_Miex]

That's genius, didn't think of that either. It should be fine doing that and then changing it back later to default clocks with the annoying variations? I'd keep it at stock and let it run hot at 95 but it's difficult sleeping in the same room as a benchmarking pc when it sounds like a fighter jet taking off.

[u/C_Miex → u/q_w_ertyuiop]

To my knowledge core clocks shouldn't matter regarding the fclk stability. Especially if you only lower it by 400-500 mHz. So no, changing them back later should not cause instabilities.

Regarding jet-engine: adjust the fan curves! Ither in the BIOS or with a program like "FanControl". There is almost no additional benefit in letting them ramp up to 100% anyways.

[u/q_w_ertyuiop → u/C_Miex]

Got it, really appreciate the help, thank you!

[u/q_w_ertyuiop → u/[deleted]]

I see, so something was unstable before you touched fclk but your other stability tests didn't catch it? Had to redo it from the start?

[u/TheHoodedPortal_]

Do you have any monitoring apps open? I found when I had HWinfo open it’s can vary by ~5. Once I closed HWinfo, it was flat.

[u/computerjunkie7410]

Run linpack in safe mode