RMA it for sure.
You should NEVER have issues like this ever with a brand new product, out of the box.
This part is opinion, but I've built a few systems, and had issues with AMD/ATI graphics, but never with NVIDIA...
My recommendation, RMA it. Get a refund. Get a GTX 660 TI, unless u MUST have a 7950
Benchmarks and prices: http://www.videocardbenchmark.net/high_end_gpus.html