More speculation and rumours about the Wii U have come from a member of the popular gaming forum Neogaf. The forum member claims that 720p appears to be the best resolution for games that use the Wii U second screen intensively, and that the controller displays games at a maximum resolution of 480p.
720p seems to be the sweet spot for definition with games running Wii U controller-intensive visuals
Wii U controller handles 480p
Wii U controller allows for viewing of on-TV action from another angle in some games
Seems that there are some third-party ports using this idea for gameplay
V5 dev kit is a little more powerful than V4, but doesn’t make for 1080p in these situations
Games can benefit from a slight visual boost over 360/PS3 and may run at a higher resolution
More simple titles may be able to run 1080p in conjunction with the controller