Sudden FPS drop while aiming

https://reddit.com/link/1ho4aij/video/um2gstvawk9e1/player

https://reddit.com/link/1ho4aij/video/i4zyl3cbwk9e1/player

Hi guys!

Recently I've got a problem with my FPS performance while aiming. Normaly I have abt. 90-100 FPS but when i go on aiming mode it drops abt. 30 FPS and sometimes it goes below 60 FPS. Is there anything I can do about?