Legit Reviews

Before we get started heres my buds specs:
Seasonic 600w
DFI NF4 Expert (12/07/2005)
AMD 4400+
2gb Crucial Ballistix
Dual XFX 7800GTX 256mb (matching bios)
250gb SE16 WD sata

Ok, I can get it all installed and run it fine and once I installed coolbits I auto detected the max and ran 3dmark05. Scored something like 11700. Went back and tinkered with the speeds again then the system goes CRAZY. Repeated reboots and wont load windows.. Could the psu not be getting enough juice? (cpu and ram are not o/c)

That PSU should be fine. Have you checked the rails?

Make sure the PSU has at least 38A on the 12V rail... When I was running the X1900 XTX CrossFire cards together my OCZ PowerStream 620W 38A power supply couldn't hack it.

Since you are overclocking (meaning increasing the power supply requirements) you might be wanting more from the rails than they can produce.

When I was pushing my PSU I would get BSOD's in 3DMark06 when I tried to benchmark and random reboots when running 3d applications.

I just looked at the SeaSonic site and saw that their 600W power supply has 36A on the combined 12V rail. I know this is not enough for the Radeon X1900 CrossFire soultion and is really pushing it on the 7800GTX SLI side too.

Keep in mind that +12V @ 5.5A must be available to each of the two PCI Express 6-pin auxiliary power supply connectors. Another +12V @ 11A must be supplied to the motherboard for dedicated graphics card use. This is on top of everything else in your case. Remember even the NVIDIA site states their numbers are the lowest that should even try SLI and that their power supply recommendations are based using standard component clock speeds.