Which one is better for gaming hd 7770ghz edition 2gb: http://www.amazon.com/XFX-FX777AZDB4-Double-1095MHz-Graphics/dp/B007A44VAE/ref=sr_1_8?s=electronics&ie=UTF8&qid=1344542806&sr=1-8&keywords=hd+7770+ghz+edition+2gb
OR
hd 6870 1gb: http://www.amazon.com/XFX-Radeon-MINIDP-PCI-E-HD687AZHFC/dp/B005C31F2M/ref=sr_1_2?s=electronics&ie=UTF8&qid=1344542885&sr=1-2&keywords=hd+6870
OR
hd 6870 1gb: http://www.amazon.com/XFX-Radeon-MINIDP-PCI-E-HD687AZHFC/dp/B005C31F2M/ref=sr_1_2?s=electronics&ie=UTF8&qid=1344542885&sr=1-2&keywords=hd+6870