MojoKid writes "For a CPU that hasn't seen the light of day, there's a great deal of debate surrounding Apple's A6 and the suggestion that it may not appear until later in 2012. The A6 is a complex bit of hardware. Rumors indicate that the chip is a quad-core Cortex-A9 CPU built on 28nm at TSMC and utilizing 3D fabrication technology. While the Cortex-A9 is a proven design, Apple's A6 will be one of the first 28nm chips on the market. The chip will serve as a test case for TSMC's introduction of both 28nm gate-last technology and 3D chip stacking. This is actually TSMC's first effort with an Apple device. The A4 and A5 have both historically been manufactured by Samsung."