I recently sold my Sapphire HD Radeon 7770 Ghz edition to a friend of mine who already had the exact same model. i told him they Crossfired well, since I had been running two of them for quite some time.
He installed them in his PC, after upgrading his PSU to a 550W. His board is a GA-970A-D3. However, when they are both installed, he does not get any display from the main video card (in the top PCIe slot), even though we can hear the system boot. I told him to try them individually to check if one of them may have fried, but they all respond well to the test and the system runs as normal.
The cards are in good shape and have a direct 6 pin line from the PSU, the PSU is new and powerful enough(I used a 450W in mine), the motherboard still boots.
Has anyone experienced that before? Is there something obvious that I may have missed? Please help us
Can he borrow your known good PSU to rule that out as an issue? Just to make sure it boots.
Only other thing I can think of is a bad CF bridge?
I have already sold my PSU. And his is brand new. What I failed to explain clearly in my post is that he purchased the new PSU because of that issue. He had a generic one installed (no mention of wattage on it, no stickers). It seemed like the only weak link in the system.
The crossfire bridge is the same I used. It may be that even if I doubt it. I will have him try another one, or both at the same time.
Besides that can you think of anything else? What would be the symptoms of a dead PCIe slot (second one)?