Nah...went into BIOS and started with changing GEN4 to GEN 2 but later put it back to GEN4 so don't think that was the problem.
I think you have to disable everything (sound,ethernet, internal GPU etc.) as well as setting above 4G decoding and disabling re bar .
I have a Tachyon....I can send you profile if you have same board.
It was fun and much more fun than running a 4090 (plug and play) ?
Worst GPU problem I have ever had
AMD eh lmao