So here's a little mystery that I have uncovered. I have two HD 4870x2's and was running them in the #1 PCI-E slot/#3 PCI-E slot (for X16 each). A few days ago I noticed under CCC that the second HD4870x2 was showing a disabled adapter. I thought the card lost one GPU core ... I was very upset.

Today for grins and giggles, I switched the second HD4870x2 to the #2 PCI-E slot and all of sudden, there is the lost adapter!! I show all four adapters. Now, if I switch the second card back to the #3 PCI-E slot, and I loose an adapter (GPU core) good chance it could be a bad PCI-E slot, right? Sounds like an RMA to me, huh?

Any thoughts?