It's a AMD Trinity based APU (according to S|A rumour). Each core is much, much better per-clock than what the 360/PS3/Wii U has. 4 Bulldozer (x86) cores and recent AMD Radeon shaders.
1.6GHz makes sense because it's effectively a laptop version (35-45W) of a desktop chip (95W) which would run at 3-4GHz. That is the base clock and there could be a Turbo mode above that.







