Blackwell Ultra B300 vs Instinct MI355X
Complete side-by-side comparison of specs, performance, memory, power efficiency, and pricing.
Blackwell Ultra B300
100
Spec Wins
Instinct MI355X
96
Detailed Specifications
Blackwell Ultra B300 — Best For
Instinct MI355X — Best For
Who Should Choose Each GPU?
Choose Blackwell Ultra B300 if you…
- ✓Need maximum CUDA/TensorRT/vLLM ecosystem compatibility
- ✓Prioritize raw FP8 throughput (7,000 vs 4,625 TFLOPS)
- ✓Running Trillion-Parameter Training workloads
- ✓Running AGI Research workloads
- ✓Running Sovereign AI workloads
Choose Instinct MI355X if you…
- ✓Working with a tighter CapEx budget (lower list price)
- ✓Running LLM Training workloads
- ✓Running Frontier AI workloads
- ✓Running HPC workloads
Verdict
The Blackwell Ultra B300 and Instinct MI355X target different priorities. Both GPUs offer the same 288GB VRAM, so the decision comes down to ecosystem and compute throughput. For training throughput, the Blackwell Ultra B300's 7,000 FP8 TFLOPS outpaces the Instinct MI355X's 4,625 TFLOPS. Teams already invested in the NVIDIA/CUDA ecosystem will have less friction with the Blackwell Ultra B300, while teams open to ROCM can benefit from the Instinct MI355X's advantages. Use our TCO Calculator to model the full 3-year cost difference for your specific utilization and power costs.
Blackwell Ultra B300 vs Instinct MI355X: Common Questions
Which is faster, Blackwell Ultra B300 or Instinct MI355X?+
In FP8 throughput, the Blackwell Ultra B300 leads with 7,000 TFLOPS vs 4,625 TFLOPS. For LLM inference, memory capacity and bandwidth often matter more than raw TFLOPS — the Instinct MI355X has more VRAM (288GB).
Is Blackwell Ultra B300 or Instinct MI355X better for LLM training?+
For LLM training at scale, the Blackwell Ultra B300 has higher raw throughput. However, the choice also depends on your software stack: Blackwell Ultra B300 offers CUDA compatibility with the widest framework support (PyTorch, JAX, TensorRT).
What is the price difference between Blackwell Ultra B300 and Instinct MI355X?+
The Blackwell Ultra B300 is estimated at $40,000 per unit and the Instinct MI355X at $30,000. Actual pricing varies by vendor, volume, and configuration. Check our Buy page for current reseller pricing.
Which GPU is more power efficient, Blackwell Ultra B300 or Instinct MI355X?+
The Instinct MI355X has a lower TDP (1400W vs 1400W). Performance-per-watt depends on your workload — for FP8 inference, divide TFLOPS by TDP: Blackwell Ultra B300 = 5.0 TFLOPS/W vs Instinct MI355X = 3.3 TFLOPS/W.