Keep getting BIOS error on ROG Crosshair X670E Hero randomly on reboots

[PrazVT]

Hey All!

So for the last couple of months, ever so often (and maybe more frequently than that), when I do a cold boot or reboot my system, I get that screen that shows there was an issue with the Post and to hit F1 to go into the BIOS.  Effectively, what I see is that the RAM defaults down to 4800 MHz.  The system's running a Ryzen 7900 + 2 x 32GB of G.Skill DDR5 6000 (and on the compatibility list for this board).  I cannot for the life of me figure out what is causing the problem.  I do have PBO + curve optimizer on -> but I did extensive core by core testing to find stable settings and just turning off PBO altogether doesn't change the behavior.  As such, don't think that's the issue.

Is it just BIOS weirdness?  As soon as I hit F1 and just and reenable EXPO, everything is fine.  But no guarantee that the next reboot will be successful.  I'm on the latest BIOS ..but this has been happening for at least the last 2-3 versions that I've updated to.

Any ideas what could be the issue?  

Thanks!

[PrazVT]

BTW - the previous 6-8 months, never had this issue.  

[Silent_Scone]

Hi @PrazVT 

It's likely that the system is failing to complete POST memory stress tests and is entering Safe Mode.

When the system does POST and boot successfully, have you conducted any stress tests?

I'd recommend using Karhu Ram Test, HCI Memtest Pro or TM5

[PrazVT]

In the past I have at least once - Cinebench, 3D Mark maybe.  Is there something specific you would suggest?  

[Silent_Scone]

Personally for memory stress testing Karhu is my #1 choice. You want to look for between 2K to 4K coverage as a minimum.