I had the same issue as you, I did update to the new 326.80 beta drivers and it didnt help (much)....what DID help though, is I moved to a Japanse Server (I am in Western Canada) so the primetime wouldnt affect me as much. I am almost confident that it has everything to do with the servers themselves. I have done virtually everything to figure it out (a variety of past drivers, memtests, pulling memory, a variety of PC cleaning tools). Try playing on a less populated server (if you can find one) and see if that helps you. Yes that means re-rolling but you can always transfer to a server of your choice if you need to be with friends.