Google TensorFlow Research Cloud is a large GPU cluster operated by Google, located in the United States, in the private sector. It came online around May 2017. At that moment it ranked number 1 among known clusters.
It is built on 4,096 Google TPU v2. That amounts to about 95.21 H100e of AI compute. The cluster draws roughly 2.69 MW. Its hardware is estimated at $39M.
Epoch AI rates the certainty of this record as likely. 1 cloud TPU = 4 TPU chips, according to the Forbes doccument and the FLOP counts we know for TPU v2