Noting that this is a fantastical rumor, I doubt that this question will be taken seriously but I thought I'd ask. Who knows, maybe someone with some expertise, or a Nintendo representative who has been given authority will answer with more than "We don't speculate on rumors".
So it's a ridiculous rumor but it has many people blazing for a real answer because, honestly, it's just really crazy yet something so many Nintendo fans want to be true. A random poster over at TV tropes claimed the following:
CPU: IBM PowerPC 7xx-based tri-core processor “Espresso” clocked at 1.24 GHz before the 3.0.0 update, 3.24 GHz after the 3.0.0 update. This is an evolution to the Broadway chip used in the Wii, is 64 bit and uses Power6 technote When IBM has said that Nintendo has licensed the Power7 tech from IBM, Nintendo is not using it for the Wii U, explaining its backwards compatibility.
GPU: AMD Radeon High Definition processor codenamed “Latte” with an eDRAM cache built onto the die clocked at 550 MHz before the 3.0.0 update, 800 MHz after the 3.0.0 update.
While this is fascinating and grandiose, I wish Nintendo would comment on it. Anyone here, with some authority and expertise, feel like sharing some insight?