I have a GA-870A-USB3 motherboard which has 4 PCIe slots on it (2 16x and 2 1x) I currently have 2 5850's running perfectly in the two 16x slots. I am trying to add another 5850 using a 1x PCIe extender cable (riser?) but I cannot get it to work. When I take out the two other cards and only connect the new card to any of the the 1x slots, the card is not recognized by the graphical part of debian (running linuxcoin 0.2b) but the bios shows up and I can see linux loading. I then get a Failed to start X server message. I am using a modified 1x PCIe cable (I took of the end to fit onto the 16 connector on the card).
Has anyone else had this problem? What can I try to fix this? Thanks.
Also the same thing happens if the other two cards are left in the mother board, and the new card works fine if connected directly into the mother board.