We just installed a XFX GeForce 9800 GTX BLACK EDITION into our XFX NForce 650i Ultra Intel motherboard. We previously had a Geforce 8800 GTS in there, but it died. Anyhow, upon installation and startup, we are experiencing problems with the screen going anywhere from perfect to completely snow covered background and varients therein. Upon this, the whole system freezes and then have to kill it.
Card Specs are
738MHz Core speed
128 CUDA Cores
512MB 256-bit GDDR3
The info label for the PSU could on the other side facing away from the opened side of the sace, you'd need to remove the PSU to see it, unless there is a viewing panel cout ot of the motherboard plate so you can remove the other side of the PC case and peek through, easier to remove the PSU, though. Make and model number.
It's most likely the PSU is under powered for the new video card.