Locked Understanding modular power supplys.

[Baronstragen]

Ok, so I have an OCZ 700W modular power supply. My graphics card has 2 8-pin PCIe connections. I only had the 8pin PSU to 6 pin PCIe connectors so I made my own. Lately, my graphics card quit working, or rather the computer wouldn't boot with the card in. (The card powered on and everything but the computer wouldn't POST) so I put an old card in there. I ordered a new cable, but it's a single 8 pin PSU to 2-8 pin PCIe connectors. Can I run this off a single 12V rail to power my card? It's an HD7970 rated @ up to 250W. Or do I need both PSU connectors?

According to my PSU specs I can run a total of 552W off of both voltage rails. See below.

Just wondered if this will work. If not I better order different cables.

Thanks in advance.

Cheers.

 

[Light_Eater]

Hi @Baronstragen
A full-sized x16 graphics card may draw up to 5.5 A at +12 V (66 W) and 75 W combined after initialization and software configuration as a "high power device". from PCIe
and additional connectors add 75 W (6-pin) or 150 W (8-pin) of +12 V
if the card needs 250W in theory 6+8 pins should do the trick
When a 6-pin connector is plugged into an 8-pin receptacle the card is notified by a missing Sense1 that it may only use up to 75 W.
I don't know about this one spliting cable to two 8 pins connectors, there should not be a problem with trying, it just won't start.

go to wiki > put 'PCI Express > go to 'power' section 2.1.3
you will have all the info and how connectors look

Man I think this cable should work, in my machine I have one 8 cable comming from PSU it splite to two 6+2 connectors
and feed a Gpu that takes 8+6

 

[Baronstragen]

Ok, well I appreciate the information. Team OS staff, please mark completed and locked, thanks