Its been occuring since a few days back. After I play for an hour or so, my game suddenly starts locking up. Best way I can explain it is that it stutters. And if I try to play against it, it just intensifies until it becomes unbearable. This gets resolved with a client reboot, but its still a reoccuring thing.
Could it be a recent update to my graphics driver? That's the only thing I can name off the top of my head that has changed.