The most logical response (from what i have heard) is the use of a nice upscale technique (this is why the PS3 version looks more smooth)... like GT4 (they are using horizontal upscale)...
And again, maybe the trend on power terms is for the PS3, but since GTA was build with the 360 in mind, maybe the engine couldn´t be adapted to use more of the PS3 teorical power...








