For me exaclty the same. There was really not any BIOS that let me boot with IF at 1900 MHz. But F11j or F12a with Agesa 1.2.0.0 boots up to 2033 MHz. 2033 MHz will hang after a few seconds in Wiondows, so that's definitly not stable, but 2000 MHz looks stable, also good AIDA64 results, but when stressing...

Maybe you can boot with your GeForce 710 and try to set PCI-e speed to Gen 3 in stead of the default Auto setting and install your 6900XT again to see if it will boot.

You're welcome!

Maybe a beta BIOS based on Agesa 1.1.9.0 will come this week, PBO2 is part of it.

- Disable Spread spectrum, than your base clock will run at 99,98 MHz.
- Ryzen cpu's don't like ueven CAS latencies, so that may be the reason why it run at 16.
- I can't boot with IF 1900 MHz, but I can boot at 1933 and higher (to 2000 MHz)....

I was having exactly the same problem, I could not boot with IF at 1900 MHz, but 1867 MHz was stable. I saw on internet that some B550 users could not boot IF 1900, but 1933 or higher was possible. Very strange, but I gave it a try yesterday and yes: I could boot with IF set to 2000 MHz and even was...