Euh, i think you mean the GTX550, when i google GF550 i get an turntable or a frying pan, so ? If you mean the GTX550 vs HD 6850 then go for the radeon it's a bit better. A GTX 560 though is better then the 6850, but more expensive. The nvidea closest to the 6850 is probably a GTX460. It also depends a bit on the game. Maybe google HD 6850 benchmarks, so you can see for yourself.