As stated in the OP, yeah the fans do run. The card has been plugged into pcie_4 I think it was (default slot for the second card for sli) and then pcie_1 by itself. Same issue both times (had a second monitor plugged into it when testing the sli)
do you use a molex adapter ( 4pin to 6+2pin PCIE ) or you plug the 6 & 8 pin PCIE directly from the PSU ?
have you tried installing the GPU in a different PC ?