Two GPUs, One Motherboard, One GPU in lspci

[CraigWatson]

OK, got bored and had another go at this. Plugged the card in, nothing. Connected a monitor, nothing. Re-seated the card, nothing.

Then I looked at the SATA ports on the side of the board and thought "aha". Turns out that the two eSATA plugs were right up against the card's cooler. The card was still seated in the PCI-E slot but the SATA ports were stopping the back end of the card slotting in properly - it's an OEM Dell 7800GTX and it's a long-format PCB.

Problem solved - CUDA drivers install fine, lspci recognises the GPU

New problem is that the GPU isn't supported for folding, which was the original purpose. D'oh!