Could be the PSU - i'm running a similar system with a 750w corsair PSu without any trouble.

In my experience BSOD's are often caused by the RAM. My motherboard auto-setup my RAM as 1033Mhz (i think) with CAS 20-6-6-6 (or something like that), and my screen was blue very often. After changing it to the correct 1666Mhz and the CAS 24-9-9-9 that was printed on the side of the RAM sticks - everything is fine. Same with my last PC - took a long time tweaking the RAM timings before it ran without BSOD's.

Then again - could be anything really