My Radeon HD 7950 from Powercolor has recently started throwing horizontal & jagged lines across the screen whenever I play a newer, more demanding, game. It also idles at 51C with two monitors, even with chassis fans at 100% it runs up to 59C with GPU Fan at 100%. I was told it could be a heating problem causing artifacting but I don't think it should be this hot in the first place. I haven't had it for 30 days even.
Please let me know what I should do or if anymore info is needed.
AMD FX 8350
AMD RADEON HD 7950
G SKILL DDR3 SDRAM 4GB X2
powercolor is known for it's junk gpus. That said, you're right this is strange behavior out of the box. A suggestion, if you're up to it. Take the heatsink off the gpu, clean all the thermal paste off the gpu and heatsink (using 90% rubbing alcohol and qtips). put new thermal compound on the heatsink where the old was (Artic Silver 5 is a good one to use) and gently put the heatsink back on. try it out, and see if temps get better. If that doesn't work then you might be forced to chose between returning it or getting an aftermarket gpu cooler like something from the Arctic Accelero lineup
I had a Powercolor HD 7950, and that packed up on me. I experienced the jagged lines on the screen when I played Far Cry 3, then the PC would reboot itself. Turns out the graphics card was faulty, as I sent it back to the seller, and I bought an XFX HD 7950 DD Edition; which is absolutely fine. I don't get the horizontal lines anymore and It idles at around 40C, which isn't bad.
If you haven't had it for 30 days and it's still under warranty, I'd return it. Get a different HD 7950 brand, for instance XFX or Sapphire, whatever is within your price range really.