From what we have tested in the workshop, we are unable to get an Intel mainboard DX79TO or DX79SI to work with a EVGA GTX 670 video card.
(The same VGA cards works with older Intel boards)
It looks like an incompatibility of some sort - with all the boards we tested reporting "error 51" on the board display accompanied by 2 beep, pause, 2 beeps and then continues to boot into windows and function normally. It must be noted that there is no display or otherwise until PC has booted into windows.
(Notes: Boards have been updated to latest bios', 1000w and 700w PSU tested. Also GTX 260 & 560 cards works with all configurations)
Lyle Stanford
South Africa
Sastec Technical Division