Fried my Gigabyte 990FX UD5 when crossfiring 2 cards

[chomper]

I was told you can Crossfire a 280x and Radeon 7970. So I gave it a try on my Gigabyte 990FX UD5. And Started to smell as if something was burning so I shutdown. Tried To power back on and no success. It burned out both my cards and my Mobo as well as my hard drive. Something is not right here. I'm running a Corsair RM1000 PSU. I bought a new Board same one and a Radeon 290 now. Same PSU and it isn't causing any issues. What could have caused that ?

I bought the PSU from a friend one of the connectors for the PCIE cards was different than one of the others ones. Even if it fits the PSU and it goes to another PSU that shouldn't cause the issue can it ?

 

[Johan45]

That would depend on the size of the wire in it possibly, if the guage was too light it might have heated up and shorted. Are you sure it was a PCIe wire and not an 8 pin CPU wire? People have gotten them confused before.

 

[chomper]

That would depend on the size of the wire in it possibly, if the guage was too light it might have heated up and shorted. Are you sure it was a PCIe wire and not an 8 pin CPU wire? People have gotten them confused before.

Its a 6 pin that goes to the PSU and splits out into 2 8 pin PCIE. The original cable that I didn't have any issues with when running it on the 7970 was an 8 pin that goes into the PSU that splits out into 2 8s.

 

[RGone]

I bought the PSU from a friend one of the connectors for the PCIE cards was different than one of the others ones. Even if it fits the PSU and it goes to another PSU that shouldn't cause the issue can it ?

Sure it could. I had one of the first of the modular supplies and the company rep I got it from said make sure you do not plug just any other brand of lead into it since the connectors were different. Not sure how but I always took him at his word. However I imagine you are still using that different brand lead and it works now. Probably just a bad connector in the PCI-e slot and heated up and bammo.
RGone...ster.

 

[Bishoff]

Its a 6 pin that goes to the PSU and splits out into 2 8 pin PCIE. The original cable that I didn't have any issues with when running it on the 7970 was an 8 pin that goes into the PSU that splits out into 2 8s.

Absolutely can and will destroy a PSU/hardware if mixing cables. Yhey are different between models, even by the same manufacturer. Corsair always recommends to use the cables that come with the PSU, or if you get a custom set that they are wired for that particular PSU.