Enterprise Training Cluster

The constraint on a training cluster is almost never the GPUs. It is the power the room can deliver and the heat it can reject. One eight-way B300 node draws around 14kW, so two of them plus the PDU headroom is already a 30kW rack, and most enterprise racks were not wired for one of those.

Air cooling is the specification to read first, and it is stated plainly on both nodes because it sets the ceiling. Air can carry a node of this density, but it needs the room to move the volume and reject the heat, and that is a survey of the facility rather than a line on the quotation. Where the density the workload justifies exceeds what the room can carry, immersion changes the arithmetic: a VasRack cabinet is rated 80 to 126kW at a pPUE under 1.1 and tolerates a plant room running to 45C, so the room does not have to be conditioned first.

With the envelope settled, the one real decision left is not the GPU. Both nodes carry the same eight HGX B300 SXM modules, the same 2.3TB of HBM3e and the same 8U chassis. They differ at the socket. The Intel 822GS reaches 86 cores per socket across 32 DIMM slots; the AMD 8126GS reaches 384 cores across 24. More cores where the data pipeline is the bottleneck, more memory slots where the host has to stage large batches.

We size from the envelope backwards. If the facility supports 40kW a rack, that is two nodes with headroom, not three that trip a breaker under load. A cluster specified this way runs at rated load, which is the only kind of capacity worth buying.