Specifications Compared
| Spec | B300 SXM6 | RTX 4090 |
|---|---|---|
| TDP | 1400W | 450W |
| VRAM | 262 GB | 24 GB |
| CUDA Cores | Not published | 16,384 |
| FP4 (dense) | 13,500 TFLOPS | Not published |
| FP8 (dense) | 4,500 TFLOPS | 330.3 TFLOPS |
| Memory Type | HBM3e | GDDR6X |
| Architecture | Blackwell Ultra | Ada Lovelace |
| FP16 (dense) | 2,250 TFLOPS | 165.2 TFLOPS |
| Form Factors | SXM6 | PCIe |
| INT8 (dense) | 187.5 TOPS | 660.6 TOPS |
| Interconnect | NVLink, PCIe 6.0, InfiniBand | PCIe 4.0 |
| Tensor Cores | Not published | 512 |
| FP32 Performance | 75 TFLOPS | 82.6 TFLOPS |
| FP64 Performance | 1.25 TFLOPS | 1.3 TFLOPS |
| Memory Bandwidth | 8,000 GB/s | 1,008 GB/s |
| FP4 (with sparsity) | 18,000 TFLOPS | Not published |
| FP8 (with sparsity) | 9,000 TFLOPS | 660.6 TFLOPS |
| FP16 (with sparsity) | 4,500 TFLOPS | 330.4 TFLOPS |
| INT8 (with sparsity) | 375 TOPS | 1,321.2 TOPS |
Performance Analysis
The B300 SXM6 delivers 2250 TFLOPS FP16 dense performance while the RTX 4090 delivers 165.2 TFLOPS FP16 dense performance. This gap means the B300 SXM6 processes FP16 dense workloads more than thirteen times faster than the RTX 4090. The B300 SXM6 also reaches 75 TFLOPS FP32 whereas the RTX 4090 reaches 82.6 TFLOPS FP32. Memory bandwidth of 8000 GB/s on the B300 SXM6 family supports larger batch sizes than the 1008 GB/s bandwidth on the RTX 4090 family. The B300 SXM6 provides 4500 TFLOPS FP16 with sparsity compared with 330.4 TFLOPS FP16 with sparsity on the RTX 4090.
Current On-Demand Offers
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When to Choose the B300 SXM6
The B300 SXM6 variant suits workloads that require 262 GB HBM3e memory and 8000 GB/s bandwidth. Its 2250 TFLOPS FP16 dense rating and NVLink interconnect make it appropriate for large scale model handling where the RTX 4090 variant cannot fit the data.
When to Choose the RTX 4090
The RTX 4090 variant fits environments limited to 450 W TDP and PCIe form factor. Its 82.6 TFLOPS FP32 rating supports tasks where the B300 SXM6 75 TFLOPS FP32 rating offers no advantage and power constraints apply.
Use Cases
The B300 SXM6 variant supplies 262 GB memory and 2250 TFLOPS FP16 dense performance that accommodate large models the RTX 4090 variant cannot hold.
The B300 SXM6 variant offers 4500 TFLOPS FP16 with sparsity and 8000 GB/s bandwidth that enable higher throughput than the RTX 4090 variant.
The B300 SXM6 variant provides 262 GB HBM3e memory that supports fine tuning of models exceeding the 24 GB limit of the RTX 4090 variant.
The RTX 4090 variant delivers 82.6 TFLOPS FP32 performance at 450 W TDP that matches diffusion workloads without the higher power draw of the B300 SXM6 variant.
The RTX 4090 variant supplies 82.6 TFLOPS FP32 performance that exceeds the 75 TFLOPS FP32 rating of the B300 SXM6 variant in precision sensitive calculations.
Frequently Asked Questions
How does FP16 dense performance differ between the B300 SXM6 variant and the RTX 4090 variant?▾
The B300 SXM6 variant achieves 2250 TFLOPS FP16 dense. The RTX 4090 variant achieves 165.2 TFLOPS FP16 dense.
What interconnect options exist on the B300 SXM6 variant versus the RTX 4090 variant?▾
The B300 SXM6 variant supports NVLink, PCIe 6.0, and InfiniBand. The RTX 4090 variant supports only PCIe 4.0.
Which GPU variant has higher memory bandwidth?▾
The B300 SXM6 family provides 8000 GB/s memory bandwidth. The RTX 4090 family provides 1008 GB/s memory bandwidth.
What TDP ratings apply to the B300 SXM6 variant and the RTX 4090 variant?▾
The B300 SXM6 family operates at 1400 W TDP. The RTX 4090 family operates at 450 W TDP.
Does the RTX 4090 variant exceed the B300 SXM6 variant in any performance metric?▾
The RTX 4090 variant reaches 82.6 TFLOPS FP32 while the B300 SXM6 variant reaches 75 TFLOPS FP32.
Which is cheaper to rent, the B300 SXM6 or the RTX 4090?▾
Cloud rental prices for both the B300 SXM6 and RTX 4090 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 B300 SXM6 have compared to the RTX 4090?▾
The B300 SXM6 has 262 GB of HBM3e memory. The RTX 4090 has 24 GB of GDDR6X memory.
Can I find B300 SXM6 and RTX 4090 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 B300 SXM6 and the RTX 4090?▾
The B300 SXM6 uses the Blackwell Ultra architecture (2025) while the RTX 4090 uses Ada Lovelace (2022). The B300 SXM6 delivers 13.6x the dense FP16 throughput (2,250 vs 165.2 TFLOPS, both without sparsity) and 7.9x the memory bandwidth of the RTX 4090.
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Related comparisons
How this page is made
- Specifications come from the NVIDIA, AMD and Intel datasheets for the B300 SXM6 and the RTX 4090. Dense and sparse throughput are listed separately.
- Prices and availability are live: every offer shown is an in-stock, on-demand listing from a provider we track, rechecked every minute.
- The written comparison (overview, performance notes, when to choose each card, verdict, use cases and FAQ) was drafted with an AI model from the specification table above and passed an automated check that rejects any figure not in that table. It was last generated on . It contains no prices; those are always read live.
- Read how we collect the data, or report an error on this page.
Next steps
- Rent B300Every current offer by provider, daily price history and a price alert.
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