Looks like Google is using the dual Fiji based AMD FirePro S9300 x2 card for deep learning:

http://www.forbes.com/sites/aarontil.../#61511a414181

Last month they announced a big win for the Tonga based FirePro S7150 x2 for the Alibaba Cloud(huge Chinese e-commerce company):

https://www.top500.org/news/amd-notc...collaboration/