macrostack

Layer 2 · head to head

AMD Instinct MI350X vs AMD Instinct MI355X

Same 288 GB, same generation. The question is whether the flagship's extra compute changes your cost per token at all.

AMD Instinct MI350XAMD 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.
Memory288 GB HBM3E288 GB HBM3E
Bandwidth8 TB/s8 TB/s
ComputeFP4/FP8; below MI355X~10 PFLOPS sparse FP4
PowerNot consistently publishedNot consistently published
InterconnectInfinity FabricInfinity Fabric
SoftwareROCmROCm
Workloadbothboth

AMD Instinct MI350X

For: The volume part of the MI350 generation, with the same 288 GB memory advantage.

The catch: Same ROCm question as the MI355X. Check that your serving stack — vLLM, SGLang, TensorRT-LLM — actually supports your model on ROCm before committing.

Economics: AMD claims 2.6x the inference throughput of an H100 on Llama 3.1 405B.

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?

Not consistently published 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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