Halo reach PC choppy fps PLS HELP

ever since I downloaded halo reach on the pc the game randomly becomes so choppy that it looks like it goes down to like 10fps, it happens multiple times every game. My game will be running just fine and then randomly get choppy and jittery when I move my mouse around, it causes me to lose fights and sometimes the whole game its super frustrating, the only way to get it to go back to normal is for me to ALT-TAB out of the game and then ALT-TAB back in, it seems to run perfectly fine after that but then it will happen again a few minutes later and I have to do this multiple times every game I play…ive tried uninstalling and reinstalling, verifying the game files and updated all drivers, nothing seems to fix it.I don’t have logitec so its not a logitec issueand yes my pc is more than powerful enough to run this game… does anyone know whats causing this and/or have a fix?im desperate to try anything ive been waiting all year to play this game on pc and its just not enjoyable right now.