Starting off, the Wii U uses a multi-chip AMD GPU sized at 12.2mm x 12.7mm, with an IBM CPU 5.2mm x 6.3mm (37.76mm2). There is also a very tiny 1.79mm x 1.48mm die on the multi-chip model which is said the be off-chip memory. The exact specifications for the CPU and GPU are still unspecified, but with the Radeon GPU, the die size is suspected by considerably larger. Taking the Redwood core’s 104mm2 and add some megs of eDRAM, you will arrive at 156.21mm2, the size of the Wii U’s CPU. Of course, this only works if 40nm process is being used which it most likely does.
The Wii U’s CPU however, is another story. All that is known about the CPU is that it is built on IBM’s 45nm SOI process with on-die eDRAM. Considering the Wii U is backwards compatible, both having the same set architecture (ISA), rumor suggests the Wii U is using the Wii’s Broadway core and multiplying it by three. With a few modifications and process node changes, taking it from 90nm to 45nm, the CPU is a capable one