I have seen this before and I'm pretty sure it is not cause by any hardware failure. Would you be interested in knowing the supposed cause of the problem?
EDIT: but, first you should sand down the PCIe contacts on the 4850x2 with fresh clean printer paper to make sure dirt and finger oils haven' accumulated on the contacts over the years. I usually fold over a small corner piece and pinch the paper over both side of the connector with my thumb and middle finger and "sand" it don't the that way, I've brought back dead motherboards and cards to life that way.
Edited by cdoublejj - 11/4/12 at 9:02pm