Specifications Compared
| Spec | GB300 | MI355X |
|---|---|---|
| TDP | 1400W | 750W |
| VRAM | 288 GB | 288 GB |
| Memory Type | HBM3e | HBM3e |
| Architecture | Blackwell Ultra | CDNA 4 |
| Form Factors | SXM | OAM |
| Interconnect | NVSwitch, NVLink | Infinity Fabric |
| FP8 Performance | 4,500 TFLOPS | 4,600 TFLOPS |
| FP16 Performance | 2,250 TFLOPS | 2,300 TFLOPS |
| FP32 Performance | 90 TFLOPS | 2300 TFLOPS |
| FP64 Performance | 45 TFLOPS | 72 TFLOPS |
| INT8 Performance | 4,500 TOPS | 4,600 TOPS |
| Memory Bandwidth | 12,000 GB/s | 8,000 GB/s |
Performance Analysis
Memory bandwidth disparities define real-world impacts: the GB300's 12000 GB/s enables larger batch sizes in training compared to the MI355X's 8000 GB/s, reducing bottlenecks in memory-bound LLM workloads. This advantage suits scenarios with massive datasets, where higher throughput accelerates iterations without spilling to slower system RAM.
FP16 and FP8 metrics show tight competition, with MI355X at 2300 TFLOPS FP16 and 4600 TFLOPS FP8 slightly ahead of GB300's 2250 TFLOPS and 4500 TFLOPS. For inference, FP8 dominance favors MI355X in low-precision serving, enabling higher throughput per watt. Training benefits from FP16 parity, but GB300's NVLink interconnect supports denser NVSwitch fabrics for multi-node scaling.
FP32 reveals a chasm: MI355X's 2300 TFLOPS vastly exceeds GB300's 90 TFLOPS, benefiting traditional HPC or graphics tasks requiring single-precision. Power efficiency tilts to MI355X at 750W TDP versus 1400W, lowering cooling demands in dense racks, though GB300's raw bandwidth compensates in AI-specific pipelines.
Live Cloud Pricing
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When to Choose the GB300 SXM6
The GB300 excels in bandwidth-intensive AI training where 12000 GB/s memory throughput supports massive models without latency penalties. NVIDIA's NVLink and NVSwitch interconnects optimize multi-GPU clusters for hyperscalers running distributed LLM fine-tuning.
Choose GB300 for CUDA-optimized ecosystems demanding SXM form factor density, as its 288 GB HBM3e pairs with superior scaling over eight-GPU nodes.
When to Choose the MI355X
The MI355X suits power-constrained environments with its 750W TDP, halving energy costs relative to GB300's 1400W while matching 288 GB VRAM. High FP32 at 2300 TFLOPS accelerates scientific simulations or legacy FP32 codes.
Opt for MI355X in ROCm-based deployments leveraging Infinity Fabric for cost-effective inference, where 4600 TFLOPS FP8 yields efficient serving at 8000 GB/s bandwidth.
Use Cases
GB300's 12000 GB/s bandwidth handles large batch sizes critical for training convergence. NVLink outperforms Infinity Fabric in multi-node setups.
FP8 performance is close at 4500 TFLOPS for GB300 and 4600 TFLOPS for MI355X, suiting high-throughput serving. Choice depends on ecosystem: CUDA or ROCm.
288 GB HBM3e on GB300 supports parameter-efficient tuning of massive models with 12000 GB/s throughput. FP16 at 2250 TFLOPS matches needs.
MI355X's 2300 TFLOPS FP32 accelerates diffusion model computations better than GB300's 90 TFLOPS. Lower 750W TDP aids creative workflows.
MI355X dominates with 2300 TFLOPS FP32 for simulations, far exceeding GB300's 90 TFLOPS. Infinity Fabric scales HPC clusters efficiently.
Frequently Asked Questions
Which has more VRAM: GB300 or MI355X?▾
Both GPUs provide identical 288 GB of HBM3e VRAM. This capacity targets large-scale AI models requiring extensive memory for parameters and activations.
How do memory bandwidths compare between GB300 and MI355X?▾
GB300 offers 12000 GB/s, outperforming MI355X's 8000 GB/s. Higher bandwidth on GB300 benefits memory-bound tasks like large-batch training.
What are the FP8 performance figures for these GPUs?▾
GB300 delivers 4500 TFLOPS FP8, while MI355X reaches 4600 TFLOPS. These metrics drive low-precision inference efficiency.
Which GPU is more power efficient?▾
MI355X consumes 750W TDP, half of GB300's 1400W. This makes MI355X preferable for dense, energy-limited deployments.
Does GB300 or MI355X have better FP32 performance?▾
MI355X provides 2300 TFLOPS FP32, dwarfing GB300's 90 TFLOPS. FP32 strength favors MI355X in HPC and traditional compute.
What interconnects do they use?▾
GB300 employs NVSwitch and NVLink for high-speed multi-GPU links. MI355X uses Infinity Fabric, optimized for AMD scaling.
Which is cheaper to rent, the GB300 or the MI355X?▾
Cloud rental prices for both the GB300 and MI355X vary by provider, configuration, and availability. This page shows live pricing from 25+ providers updated every 60 seconds. Scroll to the Live Cloud Pricing section to compare current rates.
How much VRAM does the GB300 have compared to the MI355X?▾
The GB300 has 288 GB of HBM3e memory. The MI355X has 288 GB of HBM3e memory.
Can I find GB300 and MI355X GPUs available to rent right now?▾
Yes. This page shows real-time availability across 25+ cloud GPU providers. The Live Cloud Pricing section displays only in-stock offers with current pricing.
What is the main difference between the GB300 and the MI355X?▾
The GB300 uses the Blackwell Ultra architecture (2025) while the MI355X uses CDNA 4 (2025). The MI355X delivers 1.0x the FP16 throughput and 1.5x the memory bandwidth of the GB300.