This is, for lack of a better term, one hell of a rumor. You might as well bring truck loads of salt, because there is nothing out there to back up these claims outside of the original source, which is a post at semi-popular site TV Tropes. It was a bit hard to sift through things, but thankfully Nintendo Life was able to draw out the actual rumor so we can bring it to light for you.
The CPU and GPU are built on the same package.
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.
That's one heck of a performance increase. Now, I can confirm the Wii U not only runs faster, but something definitely was boosted with the hardware itself. Games that previously had an fps issue here or there no longer do (Black Ops II campaign is now FPS issue free, as is Batman: Arkham City). Neither of those games had any updates to them at the time that I tested it out, thus it was directly related to whatever the Wii U 3.0.0 update did. Thoughts inside.