My ASUS GTX 560 Ti TOP rev 1.00 won't display any video through the DVI ports nor will it detect alongside another GPU. The LEDs on the card light up, the fans turn and the DVI ports are putting out current because they activate my HDMI switch when connected. The system does post and go into Windows with the card as the ONLY graphics adapter on my ASUS P5E MB. When an old socket 754 system the board boots on integrated graphics, a Geforce 6150SE. I recently got this card from a friend and he was having the same problems.
A few things,
1. I have both 6-pin 75w PCI-E power connectors connected from my Corsair CX600.
2. It exhibits the same behavior in two other computers.
3. None of the other computers have this behavior with any other graphics cards.
4. The card does NOT appear under GPU-z.
5. I cannot install drivers for the card, as it tells me I do not have an Nvidia card installed (the other GPU is a Radeon 2400 PRO)
6. I cannot flash the card BIOS because it cannot find compatible graphics hardware.
7. I do not have the mini-hdmi to hdmi adapter to test that port.
I read that there is some kind of BIOS problem with these cards, and one needs to put them into "Silent" mode using a toggle switch next to the power connectors. This was the case with a thread involving an MSI card. I cannot find such a switch on this card however.