JUWELS-Booster is a large GPU cluster operated by Julich Supercomputing Center, located in Germany, in the public sector. It came online around November 2020. At that moment it ranked number 3 among known clusters.
It is built on 3,744 NVIDIA A100. That amounts to about 1.2K H100e of AI compute. The cluster draws roughly 3.16 MW. Its hardware is estimated at $102M.
Epoch AI rates the certainty of this record as confirmed.