Got over 100 hours in the game, this is a NEW problem. It wont stay fullscreen for longer than 1.5 seconds at a time. Going in windowed mode fixes it but gives me unacceptably high performance hit so I do not consider that a fix. I'm already playing close to minimum requirements so that just isn't an option for me.
Things I've tried:
Updating nvidia drivers
Setting task manager priority to "high"
Disconnecting mouse and using trackpad only
Disabling antivirus software
None of the above has had any impact on my issue. I've seen it posted in numerous places around the internet but nobody has ever taken the time to report a successful fix, so its really hard to get answers. Please help!