Hey guys, been working on this issue for a long time now and just figured out that display fusion was the issue. When moving my mouse in games I will get extreme stutters/fps drops caused by display fusion eating up the CPU. The higher the polling rate on the mouse, the worse this stuttering becomes. At 500hz, the issue is almost fixed, anything above 1000hz it becomes unplayable. I've heard that disabling application hooks fixes the issue, but that disables the main reason I use display fusion.

I had the same findings as OP. it took me months to realize the problem was displayfusion. I used the compat settings to disable everything since I don't use DF for any of that. Maybe there should be some warning or something, considering it is on sold on Steam

Agreed. It took me ages to realize it was DF as well. To the point of doing a boot drive format, installing software then testing a game before creating a restore point and installing another piece of software, one by one.