Developers have indicated that the Wii U isn't as powerful in graphics terms as the PlayStation 3 and Xbox 360.
Separate development sources, speaking under condition of anonymity, told GamesIndustry International that when it comes to visuals, the Wii U is "not as capable" as Sony and Microsoft's current generation of home consoles.
"No, it's not up to the same level as the PS3 or the 360," one developer said of Nintendo's first high definition home console. "The graphics are just not as powerful."
Another source stated: "Yeah, that's true. It doesn't produce graphics as well as the PS3 or the 360. There aren't as many shaders, it's not as capable. Sure, some things are better, mostly as a result of it being a more modern design. But overall the Wii U just can't quite keep up."
The technical specifications of the Wii U, due out in time for Christmas 2012, remain unannounced. But developers have indicated that they will be able to match the quality of visuals seen on PS3 and Xbox 360 with Wii U games.
Last month Vigil, developer of Wii U launch title Darksiders 2, said the Wii U hardware was "on par" with the current generation of consoles, and that the Wii U version of the action adventure will be "pretty much the same" as the PC, PlayStation 3 and Xbox 360 versions. Nintendo will unveil the final design of the Wii U at E3 in June.