NVIDIA HGX B300
HGX B300 is the 8-GPU Blackwell Ultra baseboard NVIDIA sells to OEMs, the platform under every non-DGX B300 server. It carries 2.3 TB of HBM3e across eight 288 GB GPUs on a 14.4 TB/s NVLink 5 fabric, and unlike HGX B200 it integrates the scale-out network on the platform itself: eight ConnectX-8 SuperNICs at 800 Gb/s per GPU over PCIe Gen6, so the NIC choice OEMs used to make is now fixed by NVIDIA. Supermicro, Dell, HPE, Lenovo, Aivres and others wrap their own CPUs, chassis and cooling around it; the same baseboard ships in air-cooled 8U boxes at the 1,100 W GPU bin and in 2-OU/4U direct-liquid chassis, with the full 1,400 W bin reserved for liquid builds. It is the default OEM quote for new Blackwell capacity in 2026.
- HGX B300 is a baseboard, not a server, but it fixes more of the design than HGX B200 did: GPUs, NVSwitch fabric and the eight ConnectX-8 SuperNICs are all NVIDIA's. The OEM now differentiates only on CPU, memory, storage, chassis and cooling.
- Air-cooled B300 exists (1,100 W bin, 8U class) despite widespread claims that Blackwell Ultra is liquid-only. What is true: the full 1,400 W bin needs direct liquid, and four 8U air boxes per rack already demand ~60 kW rack power, so air works only in high-density halls.
- The 800 Gb/s per-GPU scale-out only pays off on an 800G-class fabric (Quantum-X800 or Spectrum-X SN5600-class). Budget switches and optics with the node order; at 8x 800 Gb/s per node the fabric BOM rivals mid-five-figures per node.
- Per-GPU HBM capacity, not FLOPS, is the usual reason to specify B300 over B200: 288 GB holds model shards and KV cache that would force tensor-parallel spill on 180 GB parts, and that single change often removes a whole parallelism dimension from the deployment.
- Two 'HGX B300' servers from different OEMs still differ meaningfully in CPU platform, DRAM ceiling, storage layout and serviceability. Compare full system BOMs, not the shared baseboard spec sheet.
How much does an HGX B300 server cost?
Reported street pricing for a fully configured 8-GPU HGX B300 server runs roughly $430,000 to $550,000 or more, with Aivres quoting from about $430,000. This excludes the 800G switch fabric, optics, and rack power and cooling infrastructure.
What is the difference between HGX B300 and HGX B200?
B300 carries 288 GB per GPU (2.3 TB per baseboard) versus B200's 180 GB (1.44 TB), raises the GPU power ceiling to 1,400 W liquid-cooled, adds roughly 1.5x the dense FP4 throughput, and integrates eight ConnectX-8 SuperNICs at 800 Gb/s per GPU on the platform, where HGX B200 left NIC selection to the OEM.
Is there an air-cooled HGX B300 server?
Yes. Supermicro ships an 8U air-cooled HGX B300 system (SYS-822GS-NBR) running the GPUs at the 1,100 W TDP bin, alongside 2-OU and 4U direct-liquid systems. The full 1,400 W GPU bin is only available in liquid-cooled chassis.
What is the difference between HGX B300 and DGX B300?
Same 8-GPU Blackwell Ultra platform. HGX B300 is the baseboard OEMs build their own servers around, with choice of CPU, chassis and air or liquid cooling. DGX B300 is NVIDIA's fixed-configuration, air-cooled 10U appliance on the same platform with NVIDIA-direct support.
What is the HGX B300 baseboard part number?
The 8-GPU HGX B300 baseboard circulates in distribution as NVIDIA part number 935-26287-0070-000, though in practice nearly all volume ships inside complete OEM servers rather than as bare baseboards.