Amit Parmar :
7850 should be fine on 1080p but may struggle maxing graphics on a game like Crysis 3. HD 7950 should stomp all over that.
Yeah, the 7950 will get around 30 - 45 FPS in Crysis 3 @1080p.
900p will be just fine, whiteknights. As long as you play at your monitors native resolution your games should be nice and sharp. A 900p Monitor and 7850 are a nice match. You shouldn't have to much trouble playing most games at mid to high settings. If you can, try for the 7870 or 7950.