Hooking Up GTX480 Power The instructions say you shouldn't but it seems so obvious...

[Gregory_Diamos]

This thread is really starting to turn into a flame war, but the specifications that you posted were for an 8-pin EPS power cable, not an 8-pin PCIe power cable. It says right on the website “Make sure that you don’t try to plug an 8 pin 12 volt cable into the 8 Pin PCI Express power connector on a video card. The two cables look very similar so it’s easy to get the two confused.”

[Gregory_Diamos]

double post

[AlexanderAgathos]

Those are the maximum electrical specifications of the molex connectors, which are mostly irrelevent. The parts you conveniently neglected to post from the page you linked to is the part that 100% confirms what both myself and Steve already said:

For the six pin plug:

Official cable/connector maximum wattage delivery

Voltage rail 	Number of lines 	Maximum current 	Maximum wattage

+12 volts 	3 	2.083 amps 	75 watts

For the 8 pin plug:

Official cable/connector maximum wattage delivery

Voltage rail 	Number of lines 	Maximum current 	Maximum wattage

+12 volts 	3 	4.167 	150 watts

Ie. for a GTX480 with one 6 pin and one 8 pin connect, the official specification limit is 6.25A@12V for the 6 pin plug (75W) and 12.5A@12V for the 8 pin plug (150W) = 225W from the PCI-e connectors, plus a maximum of 75W from the motherboard slot = 300W.

Great, I have confused the cables. Though I do not understand the (150 W)=225W. How do you compute?

Great - 225W I got it.

No there was not a war just a flame which we solved with physics. :-) Also it is very pedadodical for other people (including me) to know what is going on with the PSU and its supply to the GPU so 300W is the limit. Fully grasped why.

Also you said for each 6-pin and 8-pin so you meant total. Let me restore this also because I was about to loose my hair since I thought that you meant that current passed from all lines. :-)

So concluding because it is interesting verifying the numbers with the card-specs

The Motherboards through the PCI-epxress can supply 12V with 12.5A current = 75W

The PCI-e 6-pin cable can supply 12V through three lines at 2.083A = 75W

The PCI-e 8-pin cable can supply 12V through three lines at 4.167A = 150W

So for example the Nvidia GTX-275 consumes 219W at its highest load thus there is a need for 2 6pins

The GTX-480 consumes 250W so there is a need for a 6-pin and an 8-pin PCI-e in your PSU board.

Nice info if you plan to go SLI you need this info to calculate the PSU you need.

Alex.