u/necile

I got a new 9800X3D chip recently and I did the usual prep to upgrade it such as update chipset drivers and update to the latest BIOS (I tried 3 of the latest BIOS versions, that will be relevant in a second)

I had strange unexplainable behavior that lead me to believe either my RAM or the new CPU or my mobo was faulty the entire time (fine running my 7800X3D for almost 2 years but the defects were only expressed when running AM5)

So after installing the new chip in, and enabling EXPO for my ram (typical 32 gb ddr5 6000 stuff) the symptoms were, if I could remember right:

• the system failed to boot half the time (black screen before bios splash, and sometimes black screen after splash) if I just 'saved and rebooted' new settings in BIOS.
• so as long as I didn't make new changes I felt I was alright
• the worst part, I always set a nice undervolt with a PBO -20 offset on all cores. Whatever PBO I set on the 9800X3D, I noticed it would silently revert reset etc back to PBO 'enabled' instead of 'advanced' and thus all my curve optimizer settings would be reset too. I tried all combinations, simply PBO: advanced and setting zero other settings, or -1 offset (which every chip can do) would frustratingly reset PBO back to 'enabled' which was effectively off.

Fast forward feeling a bit of anxiety thinking I had a bad chip/mobo and started shopping for motherboards, I was just about to hit order on a B850 platform thinking that would solve me when I noticed one more symptom (I know, I'm not that thorough).

• despite having expo profile turned on from the very beginning of the new CPU, all indicators in Windows showed that ram was running at stock speeds and latencies. Cue me going WTF?

Long story short, everything is working PERFECTLY now, RAM running at expo, and PBO running perfectly at all-core -20 stable (and not being reset either mind you) and no weird failure to boost.

The solution was to simply turn off or revert anything under Asrock's OC or AI Tweaker or whatever it's called and do both DRAM Expo Profile as well as PBO profile under the 'Advanced' tab. Yes that tab contains the expo/xmp profiles as well. I never knew! My entire life I was setting expo in vendor and PBO in advanced, but for some reason this combination of hardware required me to do both in advanced.

I am just dumping this here so that perhaps it helps some other poor soul that comes across this issue in a google search. Cheers.