B300 vs RTX 4090

Blackwell UltravsAda LovelaceUpdated 36 days ago

The B300 emerges as the superior choice for demanding AI workloads like LLM training and inference, thanks to 288 GB VRAM and 2250 TFLOPS FP16 that handle massive scales unattainable by RTX 4090's 24 GB and 165 TFLOPS. Cost at $6.94 per hour reflects unmatched datacenter performance, making it the winner for production environments.

B300 from $7.39/hrRTX 4090 from $0.39/hr

Specifications Compared

SpecB300RTX-4090
TDP1200W450W
VRAM288 GB24 GB
Memory TypeHBM3eGDDR6X
ArchitectureBlackwell UltraAda Lovelace
Form FactorsSXMPCIe
InterconnectNVSwitch, NVLinkPCIe 4.0
FP8 Performance4,500 TFLOPS660 TFLOPS
FP16 Performance2,250 TFLOPS165 TFLOPS
FP32 Performance90 TFLOPS82.6 TFLOPS
FP64 Performance45 TFLOPS1.3 TFLOPS
INT8 Performance4,500 TOPS660 TOPS
Memory Bandwidth12,000 GB/s1,008 GB/s

Performance Analysis

Memory capacity defines the core disparity: B300's 288 GB HBM3e supports trillion-parameter models without model parallelism, unlike RTX 4090's 24 GB limit which restricts batch sizes or requires sharding for large LLMs. Bandwidth at 12000 GB/s on B300 accelerates data movement for training epochs, enabling 12 times faster throughput than RTX 4090's 1008 GB/s in memory-bound tasks like inference.

FP16 performance of 2250 TFLOPS on B300 boosts mixed-precision training speeds by over 13 times compared to RTX 4090's 165 TFLOPS, ideal for deep learning optimization. FP8 at 4500 TFLOPS favors B300 for quantized inference on massive models, nearly seven times RTX 4090's 660 TFLOPS. FP32 similarity, 90 versus 82.6 TFLOPS, means scientific simulations favor B300's scale despite comparable per-GPU rates.

Power draw underscores deployment differences: B300's 1200W TDP suits SXM datacenters with NVLink, while RTX 4090's 450W PCIe form enables dense, efficient clusters for prototyping.

Live Cloud Pricing

Real-time prices from 25+ providers. Updated every 60 seconds.

B300

ProviderGPU ModelVRAMHost SpecsRegionPriceStatusAction
RunPod
RunPod
NVIDIA B300 SXM6
262GB VRAM
$7.39/GPU/hr
VERDA
VERDA
NVIDIA B300 SXM6
262GB VRAM
$7.50/GPU/hr
Available
VERDA
VERDA
2×NVIDIA B300 SXM6
262GB VRAM
$7.50/GPU/hr
$15.00/hr total (2×)
Available
VERDA
VERDA
8×NVIDIA B300 SXM6
262GB VRAM
$7.50/GPU/hr
$60.00/hr total (8×)
Available
Scaleway
Scaleway
8×NVIDIA B300 SXM6
262GB VRAM
$8.73/GPU/hr
$69.84/hr total (8×)
Available

RTX 4090

ProviderGPU ModelVRAMHost SpecsRegionPriceStatusAction
TensorDock
TensorDock
NVIDIA GeForce RTX 4090
24GB VRAM
$0.39/GPU/hr
Available
Vast.ai
Vast.ai
NVIDIA GeForce RTX 4090
24GB VRAM
$0.44/GPU/hr
Available
Vast.ai
Vast.ai
NVIDIA GeForce RTX 4090
24GB VRAM
$0.47/GPU/hr
Available
TensorDock
TensorDock
NVIDIA GeForce RTX 4090
24GB VRAM
$0.48/GPU/hr
Available
Vast.ai
Vast.ai
NVIDIA GeForce RTX 4090
24GB VRAM
$0.53/GPU/hr
Available

Compare real-time pricing across 25+ providers

When to Choose the B300

Opt for the B300 in large-scale LLM training or inference where 288 GB VRAM handles models exceeding 100 billion parameters without partitioning. Its 12000 GB/s bandwidth supports enormous batch sizes, reducing time-to-results in enterprise environments priced from $6.94 per hour.

Datacenter workflows with NVSwitch interconnects benefit from B300's 2250 TFLOPS FP16 for rapid iterations on complex datasets.

When to Choose the RTX 4090

Choose the RTX 4090 for budget-conscious prototyping or fine-tuning models under 24 GB VRAM, available from $0.16 per hour across 96 cloud offers. Its PCIe form factor and 450W TDP enable quick setups in high-availability instances.

Consumer tasks like Stable Diffusion or small-scale inference leverage 165 TFLOPS FP16 efficiently without enterprise overhead.

Use Cases

LLM Training
B300

B300's 288 GB VRAM and 2250 TFLOPS FP16 enable training trillion-parameter models without sharding. RTX 4090's 24 GB limits scale severely.

LLM Inference
B300

4500 TFLOPS FP8 and 12000 GB/s bandwidth on B300 support high-throughput serving of large models. RTX 4090's 660 TFLOPS FP8 suits only smaller deployments.

Fine-tuning
Either

RTX 4090 handles models under 24 GB at $0.16 per hour for prototyping. B300 excels for larger adapters with 288 GB capacity.

Stable Diffusion
RTX 4090

RTX 4090's 165 TFLOPS FP16 generates images efficiently within 24 GB VRAM at low $0.48 average hourly cost. B300 overkill for consumer-scale diffusion.

Scientific Computing
B300

B300's 90 TFLOPS FP32 and NVLink suit parallel simulations on vast datasets. RTX 4090's PCIe limits multi-GPU scaling.

Frequently Asked Questions

Which has more VRAM: B300 or RTX 4090?

The B300 offers 288 GB HBM3e VRAM, 12 times more than RTX 4090's 24 GB GDDR6X. This enables B300 to load massive AI models without partitioning.

How do B300 and RTX 4090 compare in price per hour?

B300 starts at $6.94 per hour averaging $7.17 across four offers. RTX 4090 is far cheaper at $0.16 per hour averaging $0.48 across 96 offers.

Is B300 faster for AI training than RTX 4090?

Yes, B300's 2250 TFLOPS FP16 exceeds RTX 4090's 165 TFLOPS by over 13 times. Combined with 288 GB VRAM, it accelerates large-scale training significantly.

What is the memory bandwidth difference?

B300 provides 12000 GB/s, nearly 12 times RTX 4090's 1008 GB/s. Higher bandwidth reduces bottlenecks in data-heavy workloads like inference.

Can RTX 4090 replace B300 for inference?

RTX 4090's 660 TFLOPS FP8 works for small models under 24 GB VRAM. B300's 4500 TFLOPS FP8 is essential for high-volume, large-model serving.

What are the power requirements?

B300 demands 1200W TDP in SXM form with NVLink. RTX 4090 uses 450W in PCIe, suiting lower-power, dense cloud deployments.

Which is cheaper to rent, the B300 or the RTX 4090?

Cloud rental prices for both the B300 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 have compared to the RTX 4090?

The B300 has 288 GB of HBM3e memory. The RTX 4090 has 24 GB of GDDR6X memory.

Can I find B300 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 and the RTX 4090?

The B300 uses the Blackwell Ultra architecture (2025) while the RTX 4090 uses Ada Lovelace (2022). The B300 delivers 13.6x the FP16 throughput and 11.9x the memory bandwidth of the RTX 4090.