I came across a thread mentioning a conflict with certain motherboards using Realtek HD Audio so decided to investigate a bit further.
After disabling the Realtek HD Audio Manager in msconfig (Start->msconfig->Startup) and restarting my machine, my temps while playing diablo 3 immediately dropped by 20-25 degrees and i've yet to experience another crash or graphical glitch.
This may be old news, but i had to share my find incase there was anyone else like me left scratching their head over D3 performance issues on high end machines.
water cooled intel i7 2600k 3.4ghz cpu
nvidia gtx 570 x 2 sli
2x 120gb ssd in raid 0
(i don't have my mobo model on hand, but it wasn't cheap)