Frame frop bug in NA

I just played a game of ranked, and throughout I dropped frames for no reason. I have a pretty beefy computer and can run on max settings capped at 144 fps and stay there, if I uncap and go to lowest settings I got up to around 800 fps, but I was dropping and went to lowest and was only getting 135 and dropped losing about a second of game. I know its not my computer because I ran a scan and my system is at full work load and running fine, this also happened to a friend last night. I restarted computer and client and it didnt help