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Zen 3 - VDDCR SOC Load Line Calibration role in having higher FCLK stable

Nov 22, 2020
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It has been quite a few years sine I last played with OC & tweaking of the new system. Back in my times LCC was fancy feature, or it was recommended not to put it on too high levels, as it's more of a voltage boost under load than anything else.

So I bought new Zen 3 CPU and B550 board with fancy RAM so I can feel that excitement of tweaking this again.. little did I know :D

What's the current state of things? Especially for Zen 3 platforms? I'm less concerned about CPU, more about SOC LLC.

Main reason is that with current rather buggy BIOSes for B550 & X570 boards, quite a few people struggle to run FLCK clock at anything above 1600MHz without (this part is important) any random WHEA warnings (or even errors) recorded. In my example I set my platform to FLCK 1900, adjusted timings, went through all standard testing, no issues, no bluescreens, no drops to desktop. Only to discover that when I run some test, at heavy load then few WHEA 19 is recorded.

In my case, more than adjusting VSOC & related voltages, I had greatest success by applying VSOC LLC 5 (which for ASUS TUF board is highest setting). Without it, VSOC AUTO (showing 1.1V) in BIOS was never higher than 1.081 according HWiNFO, and rising under load (which is kind of funny, as VCORE does exact opposite) a little but never reaching 1.1V and once for a while WHEA error appeared.

Nowt with VSOC LLC5 it's 1.1V flat, with very occasional readings of 1.106.

Now since all I read about this platform & FCLK related voltages is that overvolting is as bad as undervolting and both will result in errors this seems more resonable approach than lets say setting 1.125 to cover this drop & lowering LLC. Or not? So what's your view on this issue? Is it safe, any other observation