This is starting to seem hopeless:

as you may have read in the video card section, I just got a Gigabyte 7900gt, and the stupid thing uses the old 4pin for aux power instead of a 6pin. now the dedicated PCI-e 12v rail is being wasted while my peripheral ail is being pounded on. does anyone know if the 4pin connector on my card is only using the 12v feed from the molex, or is it also using the 5v line. If it's the former, I may try to rig up a connection to use the 6pin to power the card. Any suggestions/warnings?

P.S. Sorry to anyone that read my other thread in the Video card section (It was technically a different question:) ).

It's easy, is there any red wire (5V) in the 6pin PCI-e? If not, it's not possible.

Well if it does need the 5v you could make a super cable that gets 5v from a molex and the 12v and 12v ground from a pci-e...

Might as well solder in a new cable, I presonally use 16awg and copper, it's cheap and effective(more so then any stock psu).

Just keep the cable @ 2ft or under.


Err, ensure the psu is discharged of course...

That's what I was thinking. I think this would be the safest bet.

I actually just tried using a rigged 3wire (12v,ground,ground) on a 4pin and it didn't get enough juice (It did exactly what it does with no molex; halted on the vga detect and beeped).

Because of this I'm starting to think it needs the 5v line too. I was thinking of taking it off of the floppy style connector I have plugged into the board right next to the card.

Can anyone confirm if this is correct before I attempt it? (If not I'll probably be a ginny pig)

This is what I'm looking at doing. Any suggestions?

The pci-e has 3 grounds and 3 12v's.

I was thinking of taking one ground and 12v from the pci-e, and the other ground and 5v from the floppy. I plan on soldering some leads to the backside of the connectors, and putting the leads into a 4pin molex. Can you think of a better way? Is there something I'm forgetting?

Thanks,

Joe

Just for a quick update:

I used a ~4" 4pin molex extension and pulled the 12v (yellow) and the ground next to it from the end opposite the card connection. I plugged the connector (with only the 5v red and the ground next to it) to the 4pin molex that I was originally using to power the card.

That supplys the 5v's that my freak of a 7900gt requires.

For the 12v line, I pinched the pins that I pulled from the connector the slightest bit and slipped two different sizes of heat shrink over each wire (one slightly bigger than the exposed pin, and the other just big enough to go over a single connection of the 6 on a pci-e plug) . With the slight "blade like" shape that pinching did to the once round pins, they fit in the front of the pci-e connectors snuggly and without forcing (one ground and 12v). I then pulled the smaller of the two sized heat shrink over the rest of the exposed pins and used a hair dryer to shrink it (My heat gun at work is ten times faster, but the hair dryer works). Once that was done I pulled the larger sized heat shrinks over both the connectors and the other heat shrink (This was done for extra support to keep the pins from getting pulled out).

I was originally planning on soldering in two new leads from the pci-e connector, but decided to go with the above method because it is completly reversable. No modifications were made to the supply, or the card. Just the 4" extension...

After that I booted up the monster and tested the voltages with a dmm. 12.2v and 5.01v, Identical to another molex on a different chain. After that I was confident enough to do some real world testing. I plugged the new line into the card and booted it up...and then there was a pop, and lots of smoke and...just kidding, it worked perfectly.

I no longer have a wasted 12v rail while one of the others is loaded. I'm happy.

I guess that wasn't much of a "quick" update was it?

If anyone would like better instructions or pictures let me know, although I couldn't find a single thing about this problem on the net. It seems like I'm the only one that has run into this problem (or thought enough to realize what I was doing to my rails all because Gigabyte decided to use the 4pin (12v and 5v) aux instead of the standard 6pin (3x12v).

Thanks for the replys WintersFury and Aeka.

-Joe

I think you may have been one of the few who realized it was a bad idea to have the card pluged in like that

Glad to know it works

Thanks for the intell! Might give it some attention myself. Not to handy with this kind off stuff myself...