A good peek inside Google's powerful and heavily customized AI calculator chip - it's called the TPU and it's a PCIe-connected ASIC akin to an FPU. The design was led by top MIPS CPU architect Norman Jouppi.
https://drive.google.com/file/d/0Bx4hafXDDq2EMzRNcy1vSUxtcEk/view
There's more info + analysis of Google's AI processor chip, the TPU, here :) https://www.nextplatform.com/2017/04/05/first-depth-look-googles-tpu-architecture/