Please help to choose which video card is better

Hi! I'm looking for new video card for gaming mostly and I need your opinion in which one is better. The choice stands between 2: ASUS GeForce GTX 560 925Mhz PCI-E 2.0 1024Mb 4200Mhz 256 bit 2xDVI Mini-HDMI HDCP or PowerColor Radeon HD 7790 1030Mhz PCI-E 3.0 1024Mb 6000Mhz 128 bit 2xDVI HDMI HDCP V2. Please also tell me why do you think each one is better.
