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Pyyan / Compare / MI400 vs B300 Blackwell Ultra

MI400 vs B300 Blackwell Ultra

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GPU & AI Chips · verified 13 Aug 2026

MI400AMDcurrent
B300 Blackwell UltraNVIDIAcurrent
3 slots left
SpecificationMI400B300 Blackwell Ultra
SummaryDouble NVIDIA's memory capacity.15 PFLOPS dense FP4.
Memory432GB HBM4288GB HBM3e
Bandwidth19.6 TB/s8 TB/s
Price—~$40–50K (verify)
VendorAMDNVIDIA
CategoryGPU & AI ChipsGPU & AI Chips
OfficialAMD ↗NVIDIA ↗

Highlighted rows are where these differ.

MI400

  • 19.6 TB/s bandwidth
  • 40 PFLOPS FP4
  • $7.2B in commitments

Best for large-model inference.

Full spec sheet →

B300 Blackwell Ultra

  • 8 TB/s memory bandwidth
  • Per-GPU pricing widely misquoted — one source cites rack pricing

Best for frontier training.

Full spec sheet →