MI355X vs B300
Spec-sheet and pricing comparison of AMD Instinct MI355X and NVIDIA B300 with links to continuously measured LLM inference benchmarks on identical workloads.
Spec-sheet comparison
| MI355X | B300 | MI355X / B300 | |
|---|---|---|---|
| Memory per chip | 288 GB HBM3e | 268 GB HBM3e | 1.07x |
| Memory bandwidth | 8 TB/s | 8 TB/s | 1.0x |
| Dense FP8 compute | 5,033 TFLOP/s | 4,500 TFLOP/s | 1.12x |
| Dense FP4 compute | 10,066 TFLOP/s | 13,500 TFLOP/s | 0.75x |
| TDP | 1,400 W | 1,200 W | 1.17x |
| Hourly rate (neocloud tier) | $2.09/hr | $2.52/hr | 0.83x |
| Scale-up world size | 8 chips | 8 chips | 1.0x |
Ratios are spec-sheet values; see the live compare pages for measured deltas.
Frequently asked questions
- Which has more memory, MI355X or B300?
- MI355X offers 288 GB HBM3e per chip versus 268 GB HBM3e on B300 (1.07x the capacity).
- How do MI355X and B300 prices compare?
- At the neocloud tier the SemiAnalysis TCO model rates MI355X at $2.09/hr versus $2.52/hr for B300. Hourly price alone is misleading; the per-dollar compare pages divide measured throughput by these rates.
- Is MI355X faster than B300 for LLM inference?
- On paper MI355X has 1.12x the dense FP8 compute of B300, but delivered tokens per second depend on the model, framework, precision and interactivity target. InferenceX measures both chips daily on identical workloads; see the live compare pages for current results.
See live benchmark results
Every number above is static hardware data. Delivered tokens per second, cost per million tokens and energy per token are measured continuously on the dashboard:
Go deeper with the SemiAnalysis models
InferenceX measures delivered inference performance. The SemiAnalysis institutional models cover the market behind these chips: who ships them, who buys them, and what they cost to own.
SemiAnalysis Accelerator & HBM Model
SKU-level AI accelerator shipments, pricing and specifications, from foundry wafer starts and HBM supply through customer-level installed base, quarterly with multi-year forecasts.
SemiAnalysis AI Cloud TCO Model
The source of the hourly rates on this page: all-in GPU cost of ownership built up from server capex, power, colocation and cost of capital, with rental price scenarios and a full cluster finance suite.