Massive screen lag
So for a long while now, I've had this thing where my screen will randomly MASSIVELY lag. Like, it takes a few seconds for the mouse to start moving.
Mostly this is workable, but if I'm watching a movie or something - the sound and actual time of the movie continues on normally - but the image is just stuck on a frame from like 10 seconds ago.
I'm not sure why this is happening, and I'm not all too sure on how to find out, either?
Whenever it happens, I quickly open the System Monitor to see if anything's taking up a lot of the CPU, but nothing ever is. I can close any processes I have running and it still won't pick up.
It seems to mostly just pick up to normal speed again randomly after anywhere between a second and 30 minutes. (Turning off and on again always fixes, but isn't really a viable solution).
Has anyone encountered something similar / have any ideas about how I can at least find out what it is that's causing this? Maybe some system background process that wouldn't show up in System Monitor..?
Thanks for any help,