According to the PCIE-SIG spec I am correct about motherboard providing 75W. Cables are 75W for each 6-pin cable and more for the 8-pin.

Sounds stupid, but would having fans attached to one of the graphics card cables disrupt it?

Dad this morning claims i may have missed a fan he plugged into one of the cables >.<

As discussed on MSN: Yes.

I still don't get how you are plugging fans and stuff into the graphics cards cables. If you got the PSU you said the other day, the graphics cards cables are standalone, there is nowhere to plug extras in. The graphics card cables at the ones on the far right in this picture, use them, they have dedicated ports for a reason.

Ah, Aaron, that's better, 75W per cable rather than 150W, lol. Means I was close, just got the board spec wrong.

Sounds like Kyhas is using 4-pin Molex to 6-pin PCI-E connector.

Yeah, 75W for the 6-pin and I have discovered it is 150W for the 8-pin.

So a Radeon 4870X2 will be 75W + 75W + 150W, 300W maximum available per card, although it doesn't actually use all of this (but comes damn close, about 250W).