02-26-2019 11:38 AM
02-26-2019 07:24 PM
I recently built a new system and have a perplexing problem that I can't seem to solve. I've tried pretty much every option and setting so I'm reaching out for help. I have a Strix Z390-E and 9700k. I've managed to get it stable to 5.0ghz at 1.330v with llc level 6. I've run 1 hour of Prime with AVX instructions disabled and stress loads are at 1.332v and temps are pretty good. One or two cores get up to 90+ degrees for a few seconds but there's no thermal throttling. However the moment I try prime with AVX instructions, it crashes . My solution was to introduce AVX offset but it seems like ANY AVX offset creates a quick hard crash in PRIME WITH AVX DISABLED.
I think this is very odd because I am using Prime with AVX instructions DISABLED like before so it should be running the same test as before. Prime WITH AVX enabled crashes but that's not surprising. I've tried increasing voltage, made much bigger AVX offsets, different LLC, etc, it seems like every time ANY AVX offset causes a hard crash. I've tried lower LLC and that seems to last a little longer before crash, but llc 5 and lower requires a MUCH higher voltage. Ie I need 1.365v at llc5 to maintain 1.332v on load and still crashes.
5.0ghz 1.33v llc6 AVX offset 0 - prime AVX disabled success, prime AVX enabled crash
5.0ghz 1.33v llc6 AVX offset 1 - prime AVX disabled crash, prime AVX enabled crash
5.0ghz 1.33v llc6 AVX offset 2 - prime AVX disabled crash, prime AVX enabled crash
5.0ghz 1.33v llc6 AVX offset 3 - prime AVX disabled crash, prime AVX enabled crash
5.0ghz 1.33v llc6 AVX offset 4 - prime AVX disabled crash, prime AVX enabled crash
5.0ghz 1.33v llc6 AVX offset 8 - prime AVX disabled crash, prime AVX enabled crash
5.0ghz 1.395v llc6 AVX offset 2 - prime AVX disabled crash, prime AVX enabled crash
5.0ghz 1.395v llc5 AVX offset 2 - prime AVX disabled crash, prime AVX enabled crash
5.0ghz 1.395v llc4 AVX offset 2 - prime AVX disabled crash, prime AVX enabled crash
I've tried many of the other settings, increase frequency from 140% to 170%, etc, nothing seems to work.
02-28-2019 09:26 AM
This is explained here.
It's a combination of guardband voltage increasing due to the AVX offset, combined with flatter loadline calibration and worse transient response.
To address this issue, raise your bios voltage and drop the LLC down a level until you get the same absolute load voltage as before. Lower LLC aids transient response greatly. Maxing PWM phase control and switching frequency will also help slightly if you do the other things along with it.
02-28-2019 11:32 AM
Thanks for your input. If you check my list of trials, my baseline is 5.0 at 1.330v and llc6. I've tried LLC5 and LLC4 at 1.395v. I did notice that LLC 4 and 5 lasted longer than LLC6 under prime non AVX. LLC6 causes a crash within minutes and LLC7 is a near instantaneous crash. I don't know if I can go LLC3 as the Vdrop will be too high and I will need a much larger vcore. However I think 1.4v+ voltage for a 5.0 OC may be a bit high in terms of temps? I will try maxing out PWM Phase control and switching frequency and report back.
Fun fact about tRDWR: these timings directly impact AVX. The tighter they are, the hotter AVX is. The looser they are, the cooler AVX is. Those of you that fear AVX, you might be able to use this to your advantage, and make those stress tests easier on yourself. I promise not to judge you.