After running for a few hours, Firefox starts making my entire computer lag, eventually to the point of freezing up for seconds at a time multiple times per minute.

Over time Firefox's video playback gets more and more janky, until it drops more frames than it shows. In task manager I can see FF using 50% of my GPU to play a 720p stream from Twitch.

Closing FF completely and reopening it fixes the problem, until it happens again.

Chrome has none of these issues.

Love the privacy, not a big fan of the performance problems.