3080Ti FE. I have not changed the GPU driver since my optimizations were done in early Dec 2022 and have had essentially flawless performance in all Ultra since then, until around the time SU12 was installed. FWIW, which isn’t much, I’ve done the update to FSUIPC, deleted and rebuilt the RC, and cleaned the DX Shader Cache. This is a brand new, severe problem and I have no clues where to look since the only change done was a Win 10 update over 10D ago. I may be able to do a System Restore which I haven’t looked into yet but will when I return home.