Ubisoft have revealed during their Watch Dogs press conference that the game will run on the following resolutions and framerate for next gen systems:
- PS4: 1080p/30fps
- Xbox One: 960p/30fps
- PC: up to 4K/framerate varies
Needless to say the PC version will be the ultimate version as Ubisoft partnered with Nvidia to take advantage of cool features such as ambient occlusion. Of course when it comes to PC the framerate will depend a lot on GPU though chances are if the game is running on a GTX you should be able to get 60 fps on 1080p.