Interesting. Plenty of work has been done with FPGAs, and a few have developed ASICs like DaDianNao in China [1]. Google though actually has the resources to deploy them in their datacenters. Microsoft explored something similar to accelerate search with FPGAs [2]. The results show that the Arria 10 (20nm latest from Altera) had about 1/4th the processing ability at 10% of the power usage of the Nvidia Tesla K40 (25w…
If you read the academic literature, they talk about 100x-3000x energy savings with asic vs GPU. So in that light Google's 10x improvement sounds low, and could certainly fit an eAsic story.
Furthermore, eAsic has fixed wires, but logic is defined via sram configuration(AFAIK) and not fixed, so it could offer a level of programmability .