The CPU inside the Wii U is a bit on the slow side, perhaps even more sluggish than the ageing CPU inside the Xbox 360 and PS3, Tekken series producer Katsuhiro Harada has told Digital Spy.

"I think maybe the game is coming along smoother than most people would think, as far as the look of the game," he told Digital Spy.

"As far as graphical processing and such, it's not much of an issue. But as far as the CPU goes, the clock is kinda low.

"I guess they're trying to keep power consumption down so we have to come up with creative ways to get around that and that's taking a little bit of time."

Asked if the Wii U CPU was slower than that of the Xbox 360 and PS3, Harada said: "Maybe a little bit."

He continued: "For example on PS3 it was kind of difficult at first, but if you made good use of the different cores, you could split up the processing tasks and you could achieve very good effects. But this is kind of a different issue than that."

Namco Bandai isn't yet discussing release date for the Wii U version of Tekken Tag 2, but Harada says he hopes it will be out "as close as possible" to the other versions set for September 14.