According to Tom's hierarchy chart, the 7770 is two tiers below the 5870. You specifically asked if you can play the game at 1920x1080 at max settings. You will certainly be able to select 1920x1080 for your resolution. As far as the various quality settings, you will have to try them and see. How was your gaming experience with the previous CoD title at 1920x1080 and max settings? Was that playable? It's reasonable to assume that new title will be more taxing, but exactly how much more demanding remains to be seen. There's also quite a few other requirements in addition to the GPU. The CPU and the amount of system RAM also factors in, but to a lesser degree. Again, I'd use your experience with previous CoD titles as a basis for an educated guess.