Video card problem with Gigabyte GA-MA770-DS3

[GnatGoSplat]

I just got a Gigabyte GA-MA770-DS3. When I insert an EVGA 8800GS video card, the computer will turn on when I press the power button, fans and drives will spin, but NO video, NO POST, and NO beep. If I replace the EVGA 8800GS with an XFX 8400GS video card, then it works! I removed and reinserted the EVGA 8800GS many times to make sure it is seated correctly, I checked the 12V power connector to video card and it's fine. Using the XFX 8400GS, I updated the F5 BIOS with F6 BIOS, experimented with a few BIOS settings, but nothing can make the EVGA 8800GS work! I removed the GA-MA770-DS3 and put back the previous GA-MA69G-S3H, every other hardware is exactly the same, and the EVGA 8800GS works just fine so my video card is definitely good.

Gigabyte tech support tells me their own 8800GS card works just fine. Has anyone else experienced such a weird problem?