4S Xeon or 2S Rome. Presumably Google has negotiated away the Platinum tax so 4S becomes more efficient than 2S.
Not sure but a 9200-series Xeon with two sockets would be 224 threads in a box.
4 socket boards (or 8) make a lot more sense than those abominations, though. Two entirely separate CPUs in one package for a vastly increased price...