I just built this pc since my last pc was doing the same thing so i was thinking it was a bad part. This is a fresh build all drivers are up to date and the only game installed is diablo3 currently. I have 2 SSD's Raid 0 and 16gig of ran and a 3.4quad core processor and 660 3gig geforce card.
Thanks for any suggestions or help.
Found the fix
Open Task Manager (CTL + ALT + DEL, "Start Task Manager")Right click the Diablo 3 processClick Set Affinity Uncheck all but one coreIf the performance improves some, try checking two cores. (Two Cores worked for me)