For me it was the one two punch of their scsi driver plus 21.5.1 that crushed my cpu performance. After I did another clean install the first thing I did once it booted was disable driver updates. Now windows still downloaded driver updates afterwards but it did not reintroduce the amd scsi driver that killed my system.
Right now I'm on 21.4.1 which brought my performance back to normal but today I enabled SAM which works with my 3900x boosting my Time Spy performance by 200 points over what it was without it.
Nice, Thanks for the follow up. I have a 5900x/6900xt setup and it appears that performance has only regressed in regards to DX11, DX10, and DX9 benchmarks. I understand that scores will deviate between drivers and setups, but Unigine Heaven, Superposition, Firestrike, 3DM11, Vantage...basically any synthetic benchmark that uses DX11 or below seems to have suffered a net loss, compared to previous drivers. I do not have the AMD SCSI driver, and I read somewhere that Microsoft pulled the last AMD SCSI driver from Win Update.
For anyone that has the same issue. My scores are down across the board for anything NOT DX12. DX12 benchmark scores increased while everything else decreased. Yes, people still use these older benchmarks on HWBot and on my personal discord server.