I am running the ASUS ROG Crosshair X670E Extreme with a Ryzen 7950X and I would like to disable hyperthreading in BIOS. I have searched for hours but I can't find any option to disable HT ? I can't believe that there is not such option. Any suggestions ?
I'm not 100% on exactly which option would do it, but try under AMD CBS. See section 6.13 / page 49 of E20466_ROG_CROSSHAIR_X670E_Series_BIOS_manual_EM_WEB.pdf. I think it's SMT that you're looking for, which AMD call "simultaneous multithreading"; their equivalent of hyperthreading (Intel HT). I believe ASUS are incorrect to call it "symmetric multithreading" in the manual, as that doesn't seem to be how AMD describe SMT. It may also be controllable in Ryzen Master.