DDR5 8000 stability

0121danwilliams84

0121danwilliams84

0121danwilliams84

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Hi all, I am trying to get my team group Hynix a die 7200 kit stable at 8000 @ 38, 48, 48, 84. The rest of the timings are set to auto.

Using 14900KS and Apex Encore.

I have the voltages as so:

VDD/VDDQ: 1.45
SA: 1.2
TX: 1.3
IMC: 1.45

It’s stable in stability tests and games but randomly hard crashes (either system restart or freeze.)

It only seems to crash at idle, usually when I leave the system unattended.

Has anyone got an idea what I may need to target to try and sort this kind of instability?

Thanks
 
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So I’d run something like y-cruncher and OCCT to test if CPU stable as random crashing point to a failing chip. If those tests pass then run memory intensive tests in gear1/2 as you need stability in both.
 
8000MT is into hit and miss territory with LGA1700 and Raptor Lake even on the top spec boards which are supposedly 8000+MT capable you often need everything to align to get it fully stable - RAM, motherboard and the CPU memory controller quality. You are probably at the point where sub-timings need tweaking - so might be worth backing off the main timings a bit to see if it is even possible at all.
 
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0121danwilliams84 said:
Hi all, I am trying to get my team group Hynix a die 7200 kit stable at 8000 @ 38, 48, 48, 84. The rest of the timings are set to auto.

Using 14900KS and Apex Encore.

I have the voltages as so:

VDD/VDDQ: 1.45
SA: 1.2
TX: 1.3
IMC: 1.45

It’s stable in stability tests and games but randomly hard crashes (either system restart or freeze.)

It only seems to crash at idle, usually when I leave the system unattended.

Has anyone got an idea what I may need to target to try and sort this kind of instability?

Thanks
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Suspect SA in the first instance being too low. Try 1.3-1.35.
TX 1.4, VDD/VDDQ 1.5/1.47 might help.

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My settings for 8200C36 using 7200 sticks and the silver Apex linked above if you feel like having a go. Depending how well you cool the RAM you should be able get a higher TREFI, 262k is the max.
 
Thanks for the advice!

Will try changing a few settings.

I was thinking of looking at SA next.

Is SA kind of ‘linked’ to TX. Do I need to alter that when I change SA up or down?

I believe that VDD/VDDQ and IMC scale more with memory clock and other voltages are more of a sweet spot.

The 14900KS is direct die and running at 14900k clocks (undervolted) and I am pretty sure that is 100% stable.
 
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Forgot the exact reasoning now as those settings are nearly 3 years old. But try those voltages first. If that doesn’t work then it might just be your IMC not being able to handle it. Not uncommon for some being to only do 7600/7800 etc.

Edit: also worth trying expo tweaked and then putting timings in. Think it’s to do with the training iirc.
 
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8000 stable at those clocks is very dependent on the silicon lottery gods

Agreeee with the previous post in that you'll not see any noticeable gain over 7200
 
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