Anyway, based on buildzoid's video the GPU VRM power input is infact split between the PCI-E slot and PCI-E power connector (and not just shorted), like I expected. w1zzard from TPU promised to make me some measurements to find out the exact structure of the card. If the power source for the GPU VRM phases are split 50/50 between PCI-E slot and the PCI-E power connector, I should be able to remedy the excess power draw from the slot quite easily. The fix could be applied either by Afterburner or by using a modified bios (once flash tools are available). The fix doesn't affect the total power draw of the card or the performance.