macrostack

Layer 2 · head to head

NVIDIA B200 vs AMD Instinct MI355X

The memory argument, stated cleanly: 192 GB of CUDA against 288 GB of ROCm.

NVIDIA B200AMD Instinct MI355X
Can you get itRentable by the hour from multiple clouds; purchasable at scale.Rentable by the hour from multiple clouds; purchasable at scale.
Memory192 GB HBM3E288 GB HBM3E
Bandwidth8 TB/s8 TB/s
ComputeFP4 and FP8 sparse; vendor figures vary by configuration~10 PFLOPS sparse FP4
PowerUp to 1,000 W per GPU in liquid-cooled configurationsNot consistently published
InterconnectNVLink 5Infinity Fabric
SoftwareCUDAROCm
Workloadbothboth

NVIDIA B200

For: The default frontier accelerator. If you have no specific reason to choose otherwise, this is what the market chose.

The catch: 192 GB is less memory than AMD's MI355X at 288 GB, and for memory-bound inference that gap is the whole argument.

Economics: CUDA maturity is the real product. The chip is competitive; the software moat is why it wins procurement.

AMD Instinct MI355X

For: Memory-bound inference. 288 GB against Blackwell's 192 GB is the cleanest technical argument AMD has made in a decade.

The catch: ROCm, not CUDA. The gap has narrowed sharply but it is still the reason procurement teams say no, and porting cost is real.

Economics: AMD positions this as the best price-per-token part for inference at scale, and claims 2.6x H100 inference throughput on Llama 3.1 405B for the MI350X.

Before either — can you power it?

Up to 1,000 W per GPU in liquid-cooled configurations against Not consistently published. In 2026 that comparison usually matters more than the FLOPS one: the US interconnection queue exceeds 2,600 GW with waits approaching five years, and roughly 80% of projects withdraw before energising.

Layer 1 — Energy · Nuclear vs gas · Direct-to-chip cooling

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Specifications verified 2026-09-09. We take no commission at this layer, on either part.

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