As of this AM with patch 6.45, Screen Space Ambient Occlusion in the System Config, Graphics Settings causes MAJOR stuttering issues not FPS loss even though it appears to be.
I have tested this on two computers, both Alienware.
Desktop: RTX 3080
Laptop: RTX 3070ti
32GB RAM
NVME
Windows 11 Pro
Drivers are up to date, did not do this before 6.45.