RTX PRO 6000 Blackwell vs Instinct MI355X
NVIDIA RTX PRO 6000 Blackwell (Blackwell, 96 GB) against AMD Instinct MI355X (CDNA 4, 288 GB): memory, compute, power and rental price, compared for LLM inference and training.
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Side-by-Side Specifications
| Spec | RTX PRO 6000 Blackwell | Instinct MI355X |
|---|---|---|
| Architecture | Blackwell | CDNA 4 |
| Memory | 96 GB GDDR7 | 288 GB HBM3e |
| Memory bandwidth | 1,792 GB/s | 8,000 GB/s |
| FP16 tensor compute | 1,000 TFLOPS | 5,000 TFLOPS |
| INT8 tensor compute | 2,000 TOPS | 10,100 TOPS |
| Interconnect | PCIe 5.0 · 128 GB/s | Infinity Fabric 4 · 1075 GB/s |
| TDP | 600 W | 1400 W |
| Est. on-demand price | ~$5.00/h | ~$13.00/h |
| FP16 TFLOPS per $/h | 200 | 385 |
Highlighted values indicate the stronger spec. Hourly rates are indicative on-demand estimates.
Verdict
Raw performance: The Instinct MI355X leads on FP16 tensor compute (5.0x advantage), which translates directly into higher token throughput for inference and shorter training steps.
Memory: With 288 GB per card, the Instinct MI355X fits larger models on fewer GPUs — fewer cards means less inter-GPU communication and simpler deployments.
Value: At current on-demand rates, the Instinct MI355X delivers more compute per dollar (385 vs 200 FP16 TFLOPS per $/h). If your model fits in its VRAM budget, it is usually the more economical choice.
GPUs Needed for Popular LLMs
Cards required to serve each model at 8-bit quantization (with 20% overhead for activations and KV cache).
| Model | VRAM (8-bit) | RTX PRO 6000 Blackwell | Instinct MI355X |
|---|---|---|---|
| GPT-5.6 Sol | 2682 GB | 28x | 10x |
| DeepSeek V4 Pro (671B) | 750 GB | 8x | 3x |
| Muse Spark 1.1 | 335 GB | 4x | 2x |
| Claude 5 Sonnet (175B) | 196 GB | 3x | 1x |
| Nova Premier (80B) | 89 GB | 1x | 1x |
| Nova Core (34B) | 38 GB | 1x | 1x |
| Nova Lite (12B) | 13 GB | 1x | 1x |
| Phi 3.5 (3.8B) | 4 GB | 1x | 1x |
Frequently Asked Questions
Which is better for LLM inference: RTX PRO 6000 Blackwell or Instinct MI355X?
The Instinct MI355X delivers more raw FP16 compute (5,000 TFLOPS) and the Instinct MI355X offers the most memory per card (288 GB). For cost-efficiency, the Instinct MI355X currently gives more FP16 TFLOPS per dollar of on-demand rental (385 vs 200 TFLOPS per $/h).
How much more memory does the Instinct MI355X have?
The RTX PRO 6000 Blackwell has 96 GB of GDDR7 versus 288 GB of HBM3e for the Instinct MI355X — a ratio of 3.00x in favor of the Instinct MI355X. More VRAM per card means fewer GPUs to fit a given model.
Is the RTX PRO 6000 Blackwell or the Instinct MI355X cheaper to rent?
Estimated on-demand rates are ~$5.00/h for the RTX PRO 6000 Blackwell and ~$13.00/h for the Instinct MI355X. Raw hourly price is only part of the story: normalize by throughput (TFLOPS per $/h) and by how many cards you need for your model's VRAM.
How do the RTX PRO 6000 Blackwell and Instinct MI355X compare on power?
The RTX PRO 6000 Blackwell has a TDP of 600W versus 1400W for the Instinct MI355X. FP16 compute per watt: 1.7 vs 3.6 TFLOPS/W.
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Rent the RTX PRO 6000 Blackwell or Instinct MI355X by the hour instead of buying hardware.
