That has not stopped the hacking community from getting in there and trying to solve what can only be described as a megahertz mystery. Acclaimed hacker Mercan42 claims that the CPU in the Wii U is clocked at 1.24Ghz, while the graphics GPU is clocked at 550Mhz, which is about what we have suspected. The CPU is described as similar to the Wii’s Broadway PowerPC CPU, but with three 750-style cores with more cache and some other additional internal enhancements.
The AMD-designed GPU clocked at 550Mhz does seem about right. Our best guess is that it has between 320 and 400 Stream processors. The codename for the GPU design is said to be Latte, which would go with the Espresso codename that the CPU has been said to carry for some time.
While there has been no confirmation to back this up, we have to think that this source is pretty reliable; and if you do the math and look at the clock speeds of the GameCube and then the Wii, it does seem the numbers do make sense. Again, we are told that optimization of the CPU and added instruction set features could yield some performance advantages that you can’t get by brute force clock speed alone. The 1.24Ghz number, along with the 550Mhz, would explain if the chip is using the suspected 45nm process that they are able to get away with cooling that is minimal when compared to other solutions.
Read more here.
http://www.eurogamer.net/articles/digitalfoundry-wii-hacker-reveals-wii-u-cpu-secrets