The specs you'll find below are said to have come directly from Nintendo development support group Wario World, though that really doesn't count for much as far as legitimacy is concerned. Still, they look pretty legit, and are an interesting read if nothing else.
VGLeaks says that this information comes directly from an anonymous source, straight from that Nintendo dev group.
The CPU "Espresso" has 3 cores, the GPU is a AMD Radeon affair set up for HD graphics (up to 1080p), and there's 1GB of memory to play with. Storage memory is set at 8GB, but you'll supplement that with SD cards. See the full rumored specs below.
What do you think? Decent? Sufficient? Not enough?
“Espresso” CPU on the Wii U has three enhanced Broadway cores
“GPU7” AMD Radeon™-based High Definition GPU. Unique API = GX2, which supports Shader Model 4.0 (DirectX 10.1 and OpenGL 3.3 equivalent functionality)
Mem1 = 32MB Mem2 = 1GB (that applications can use)
Internal 8 GB with support for SD Cards (SD Cards up to 2GB/ SDHC Cards up to 32GB) and External USB Connected Hard Drives
802.11 b/g/n Wifi
Supports 1080p, 1080i, 720p, 480p and 480i
Video Cables Supported:
Compatible cables include HDMI, Wii D-Terminal, Wii Component Video, Wii RGB, Wii S-Video Stereo AV and Wii AV.
Four USB 2.0 Ports