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Pyyan / Compare / B300 Blackwell Ultra vs MI400

B300 Blackwell Ultra vs MI400

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GPU & AI Chips · verified 13 Aug 2026

B300 Blackwell UltraNVIDIAcurrent
MI400AMDcurrent
3 slots left
SpecificationB300 Blackwell UltraMI400
Summary15 PFLOPS dense FP4.Double NVIDIA's memory capacity.
Memory288GB HBM3e432GB HBM4
Bandwidth8 TB/s19.6 TB/s
Price~$40–50K (verify)—
VendorNVIDIAAMD
CategoryGPU & AI ChipsGPU & AI Chips
OfficialNVIDIA ↗AMD ↗

Highlighted rows are where these differ.

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 →

MI400

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

Best for large-model inference.

Full spec sheet →