Thanks for the welcome all!
Howdy
Good to meet another Texan on here, from whereabouts are you from?
San Antonio, born and raised.
Sure you power supply can handle that? I have a 7970 + 7990 (2x7970) and adding a 3rd card destabilizes the system. And that's with a 1200w PS.
I am mining on four cards with a 1500W power supply, but mdbssm is right, check to make sure how much you need per card and try to double it.
I have my machine plugged into a Kill-A-Watt to measure how much wattage I'm pulling. At full load with 3 cards I am in the 800's. I have a Seasonic 1200W gold+ certified PSU. If my PC was locking up or shutting down while all 4 cards were running I can see how maybe it'd be a power issue. But, my computer will not even post. It hardly pulls any power at all when i hit the power button and just sits there. Guessing my motherboard doesn't allow all 3 PCIe x1 and the x16 to be used all at the same time or something. I've tried all the PCIe connections in different combinations, can use any 3 and get the cards to work, but once i try 4 i get nada.
Was hoping to post my problem in the hardware section on the forums but reaching 4 hours of active forum time is looking to be a challenge!