OBS loads the video card at idle by 90-100%. What could be the problem?

Question

Windows

Hello everyone))) I compare with rainbow six siege. Everything worked fine, but once again I wanted to stream and was stunned. With a normal game without running obs, the game gives out 280-320 fps. Playing 2K. As soon as I start obs, the fps drops to 200, if I start streaming or recording, the fps drops to 150. There is one more feature: if I turn on the webcam display, the fps squats even more (there is another joke: I have a frame on top of the webcam multimedia file (avi) weighs 8GB, if you turn on this frame, then the fps drops to 20-30 frames). The settings are the same, nothing has changed, not updated, not flashed. What kind of magic is not clear. In the manager, the load of 95% gpu shows only obs with all the jokes described above)))) the game process eats the remaining 5%.
I've been struggling with this problem for 3 days now, reinstalled Windows, set everything up manually, new profiles and scenes. Tried in Windows on / off the game mode did not help. I updated all the drivers for the mother (lan, bluetooth, wifi, audio, chipset, etc. Nothing helps.

Win 10 21H1
Mother asus e-gaming z390 Proc
i9 9900k
Ram 32gb gskill 3200
Gpu 3080 msi trio
I used xmp in bios 1
All programs and games on m2 from Samsung
It costs 3 monitors.All
components do not overheat.In

short, nothing happened to the computer at all, but for some reason, at one fine moment, with obs turned on, everything became terribly buggy.Before that, I streamed in Full settings that in games as in obs.I would be
grateful for help))))