I did not find and reference to the physical size and power needs of Deep mind.
https://en.wikipedia.org/wiki/Watson_%28computer%29
From the wikipedia article:
Watson is the computer that beat the humans at Jeopardy. It was rather large. And not at all mobile. The system is workload-optimized, integrating massively parallel POWER7 processors and built on IBM's DeepQA technology,which it uses to generate hypotheses, gather massive evidence, and analyze data.[2] Watson employs a cluster of ninety IBM Power 750 servers, each of which uses a 3.5 GHz POWER7 eight core processor, with four threads per core. In total, the system has 2,880 POWER7 processor threads and 16 terabytes of RAM.