I installed Vista x64 RC2 on this machine 165 Opteron, Leadtek 7800GT, A8N32-SLI Deluxe, 2gig corsair 3200 ram, 4x36gig raptors in raid0. NO Over Clock as well It clean installed with NO drama's what so ever and it recognised the raid array straight off and installed onto that array natively(no added drivers) On this machine Vista x64 is so much better then Vista x86 which is what I had installed before. About the main thing is the video drivers from NV still need a fair bit of work. Games have tearing in them. XP doesnt Nero instals but doesnt work. Could be something withhow bloated Nero is now. Ashampoo Burning Studio 5 does. So .......