B300 SXM6 vs RTX 3090

Blackwell UltravsAmpereUpdated 35 days ago

The B300 emerges as the clear winner for dominant AI use cases like LLM training and inference: its 288 GB VRAM and 2250 TFLOPS FP16 enable scaling unattainable on RTX 3090, justifying $6.44 per hour average against $0.45 for high-volume cloud deployments.

B300 SXM6 from $7.39/hrRTX 3090 from $0.20/hr

Specifications Compared

SpecB300RTX-3090
TDP1200W350W
VRAM288 GB24 GB
Memory TypeHBM3eGDDR6X
ArchitectureBlackwell UltraAmpere
Form FactorsSXMPCIe
InterconnectNVSwitch, NVLinkNVLink
FP8 Performance4,500 TFLOPS
FP16 Performance2,250 TFLOPS35.6 TFLOPS
FP32 Performance90 TFLOPS35.6 TFLOPS
FP64 Performance45 TFLOPS
INT8 Performance4,500 TOPS
Memory Bandwidth12,000 GB/s936 GB/s

Performance Analysis

Raw compute reveals stark contrasts: the B300 delivers 2250 TFLOPS in FP16 for training large models, 63 times the RTX 3090's 35.6 TFLOPS, while FP32 stands at 90 TFLOPS versus 35.6 TFLOPS, more than doubling single-precision needs for scientific simulations. The FP16 to FP32 delta on the B300, 25:1 ratio, optimizes mixed-precision training, reducing memory use without accuracy loss, unlike the RTX 3090's balanced 1:1 ratio suited to graphics.

Memory specs transform real-world usage: 288 GB VRAM on the B300 supports batch sizes up to 12 times larger than the RTX 3090's 24 GB limit, fitting trillion-parameter LLMs entirely in memory. Bandwidth of 12000 GB/s versus 936 GB/s cuts data bottlenecks, speeding inference by enabling 12.8 times faster tensor movements. Power draw hits 1200W for B300 versus 350W for RTX 3090, demanding robust cooling but yielding density in clusters via NVSwitch over PCIe limitations.

Interconnects favor enterprise: B300's NVSwitch and NVLink scale multi-GPU setups beyond RTX 3090's NVLink, ideal for distributed training.

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
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 3090

ProviderGPU ModelVRAMHost SpecsRegionPriceStatusAction
TensorDock
TensorDock
NVIDIA GeForce RTX 3090
24GB VRAM
$0.20/GPU/hr
Available
TensorDock
TensorDock
NVIDIA GeForce RTX 3090
24GB VRAM
$0.21/GPU/hr
Available
Vast.ai
Vast.ai
4×NVIDIA GeForce RTX 3090
24GB VRAM
$0.25/GPU/hr
$1.01/hr total (4×)
Available
Vast.ai
Vast.ai
4×NVIDIA GeForce RTX 3090
24GB VRAM
$0.27/GPU/hr
$1.07/hr total (4×)
Available
LeaderGPU
LeaderGPU
8×NVIDIA GeForce RTX 3090
24GB VRAM
$0.29/GPU/hr
$2.29/hr total (8×)
Available

Compare real-time pricing across 25+ providers

When to Choose the B300 SXM6

Opt for the B300 in large-scale AI training or inference where models exceed 24 GB VRAM, such as 1T-parameter LLMs leveraging 288 GB HBM3e. Its 2250 TFLOPS FP16 and 12000 GB/s bandwidth handle massive batches and datasets efficiently, with NVSwitch enabling seamless multi-GPU scaling. Cloud users prioritize throughput over cost at $2.45 per hour starting price for production workloads.

When to Choose the RTX 3090

Select the RTX 3090 for budget-conscious prototyping, fine-tuning small models under 24 GB, or Stable Diffusion tasks where 35.6 TFLOPS FP16 suffices. At $0.08 per hour starting and 44 cloud offers, it provides accessible entry for individuals or SMBs avoiding 1200W TDP infrastructure. PCIe form factor suits single-node experimentation without NVSwitch complexity.

Use Cases

LLM Training
B300 SXM6

B300's 288 GB VRAM and 2250 TFLOPS FP16 support trillion-parameter models with large batches, far beyond RTX 3090's 24 GB limit.

LLM Inference
B300 SXM6

4500 TFLOPS FP8 and 12000 GB/s bandwidth on B300 deliver low-latency serving for massive models; RTX 3090 struggles with VRAM constraints.

Fine-tuning
Either

RTX 3090 handles sub-24 GB models cost-effectively at $0.08 per hour; B300 excels for larger ones needing 288 GB.

Stable Diffusion
RTX 3090

RTX 3090's 35.6 TFLOPS FP16 and 24 GB GDDR6X suffice for image generation at $0.45 per hour average, matching consumer needs.

Scientific Computing
B300 SXM6

B300's 90 TFLOPS FP32 and NVSwitch scale simulations; RTX 3090's 35.6 TFLOPS limits complex HPC workloads.

Frequently Asked Questions

Which GPU has more VRAM?

The B300 provides 288 GB HBM3e VRAM, 12 times the RTX 3090's 24 GB GDDR6X. This enables larger models without offloading.

What is the performance difference in FP16?

B300 achieves 2250 TFLOPS FP16, 63 times the RTX 3090's 35.6 TFLOPS. Training accelerates dramatically on the newer GPU.

How do cloud prices compare?

RTX 3090 starts at $0.08 per hour averaging $0.45 across 44 offers; B300 SXM6 begins at $2.45 per hour averaging $6.44 over 7 offers.

Which has higher memory bandwidth?

B300 offers 12000 GB/s, 12.8 times the RTX 3090's 936 GB/s. Data throughput improves for bandwidth-bound tasks.

What are the power requirements?

B300 demands 1200W TDP in SXM form; RTX 3090 uses 350W in PCIe. Datacenter cooling suits B300, desktops fit RTX 3090.

Can RTX 3090 handle large LLMs?

RTX 3090's 24 GB limits it to models under that threshold; B300's 288 GB manages much larger LLMs in full precision.

Which is cheaper to rent, the B300 or the RTX 3090?

Cloud rental prices for both the B300 and RTX 3090 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 3090?

The B300 has 288 GB of HBM3e memory. The RTX 3090 has 24 GB of GDDR6X memory.

Can I find B300 and RTX 3090 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 3090?

The B300 uses the Blackwell Ultra architecture (2025) while the RTX 3090 uses Ampere (2020). The B300 delivers 63.2x the FP16 throughput and 12.8x the memory bandwidth of the RTX 3090.

B300 SXM6 vs RTX 3090: 63.2x FP16 Gap, 288GB vs 24GB | GPUPerHour