B300 SXM6 vs RTX 4090

Blackwell UltravsAda LovelaceUpdated 35 days ago

The B300 emerges as the superior choice for dominant AI workloads like LLM training and inference: its 288 GB VRAM and 2250 TFLOPS FP16 enable scaling massive models unattainable on the RTX 4090's 24 GB and 165 TFLOPS. Despite 15 times higher pricing, performance gains justify enterprise adoption over consumer alternatives.

B300 SXM6 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

The B300's FP16 performance of 2250 TFLOPS vastly exceeds the RTX 4090's 165 TFLOPS, accelerating mixed-precision training for deep learning models by over 13 times in theoretical throughput. FP32 rates show 90 TFLOPS on the B300 against 82.6 TFLOPS on the RTX 4090, indicating similar single-precision compute but B300 superiority in AI pipelines blending precisions. For inference, the B300's 4500 TFLOPS FP8 crushes the 4090's 660 TFLOPS, enabling faster low-precision deployments. Memory bandwidth defines real-world limits: 12000 GB/s on the B300 supports enormous batch sizes in large models, preventing bottlenecks that cap the RTX 4090's 1008 GB/s at smaller datasets. The B300's 288 GB VRAM handles models exceeding 100 billion parameters without swapping, while 24 GB on the RTX 4090 restricts to under 20 billion. Higher 1200W TDP and NVLink interconnect allow scaled multi-GPU training, contrasting the 450W PCIe setup.

Live Cloud Pricing

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

B300 SXM6

ProviderGPU ModelVRAMHost SpecsRegionPriceStatusAction
RunPod
RunPod
NVIDIA B300 SXM6
262GB VRAM
$7.39/GPU/hr
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
TensorDock
TensorDock
NVIDIA GeForce RTX 4090
24GB VRAM
$0.48/GPU/hr
Available
Vast.ai
Vast.ai
4×NVIDIA GeForce RTX 4090
24GB VRAM
$0.53/GPU/hr
$2.13/hr total (4×)
Available
Vast.ai
Vast.ai
4×NVIDIA GeForce RTX 4090
24GB VRAM
$0.67/GPU/hr
$2.67/hr total (4×)
Available
Vast.ai
Vast.ai
NVIDIA GeForce RTX 4090
24GB VRAM
$0.67/GPU/hr
Available

Compare real-time pricing across 25+ providers

When to Choose the B300 SXM6

The B300 excels in large-scale LLM training and inference where 288 GB VRAM fits trillion-parameter models without partitioning. Its 12000 GB/s bandwidth sustains high throughput for batch sizes over 1000, ideal for enterprise data centers. Cloud pricing at $2.45 per hour justifies use in production clusters leveraging NVSwitch for 100+ GPU interconnects.

When to Choose the RTX 4090

The RTX 4090 suits prototyping, fine-tuning small models, and cost-sensitive tasks with 24 GB VRAM handling up to 70B parameter LLMs quantized. At $0.16 per hour average $0.46, it offers value for individual developers or Stable Diffusion workflows. PCIe form factor enables easy desktop or small server integration without specialized cooling.

Use Cases

LLM Training
B300 SXM6

B300's 288 GB VRAM and 2250 TFLOPS FP16 support training trillion-parameter models with large batches. RTX 4090's 24 GB limits scale.

LLM Inference
B300 SXM6

4500 TFLOPS FP8 and 12000 GB/s bandwidth on B300 deliver high-throughput serving for production. RTX 4090 suffices only for small deployments.

Fine-tuning
Either

RTX 4090 handles 70B models at $0.16 per hour for prototyping; B300 accelerates at scale with 288 GB VRAM.

Stable Diffusion
RTX 4090

24 GB VRAM and 165 TFLOPS FP16 meet image generation needs cost-effectively at $0.46 average hourly rate. B300 overkill for single-user tasks.

Scientific Computing
B300 SXM6

90 TFLOPS FP32 and NVLink interconnect optimize simulations across clusters. RTX 4090's PCIe limits multi-GPU efficiency.

Frequently Asked Questions

What is the VRAM capacity of NVIDIA B300 versus RTX 4090?

The B300 provides 288 GB HBM3e VRAM, dwarfing the RTX 4090's 24 GB GDDR6X. This enables B300 to load massive AI models without offloading. RTX 4090 suits smaller workloads.

How do FP16 performances compare between B300 and RTX 4090?

B300 achieves 2250 TFLOPS FP16, over 13 times the RTX 4090's 165 TFLOPS. This boosts training speed significantly. Inference also benefits from the gap.

What are the current cloud pricing differences?

B300 rentals start at $2.45 per hour with $6.44 average across 7 offers. RTX 4090 begins at $0.16 per hour averaging $0.46 over 108 offers. Budget drives RTX 4090 choice.

Is B300 better for large language model training?

Yes, B300's 288 GB VRAM and 12000 GB/s bandwidth handle trillion-parameter LLMs. RTX 4090's 24 GB restricts to smaller scales. Pricing reflects capability.

Can RTX 4090 replace B300 in AI inference?

RTX 4090's 660 TFLOPS FP8 works for low-volume inference on 70B models. B300's 4500 TFLOPS scales to enterprise throughput. Cost favors 4090 for prototypes.

What interconnects do these GPUs use?

B300 employs NVSwitch and NVLink for cluster scaling. RTX 4090 uses PCIe 4.0 for single-node setups. This defines multi-GPU viability.

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.

B300 SXM6 vs RTX 4090: 13.6x FP16 Gap, 288GB vs 24GB | GPUPerHour