L40S vs RTX 4090: Which GPU Should You Choose?
This page settles whether L40S or RTX 4090 is the better rental for your workload, using observed cloud pricing, published hardware specifications, and workload-level cost estimates.
Choose L40S when its larger memory lets the job stay on one GPU; choose RTX 4090 when the job fits one card and rental price matters, given an A-to-B on-demand price ratio of 2.86, except when L40S avoids a multi-GPU split.
Run one short A/B benchmark of your representative job at the L40S on-demand minimum of $0.80 and the RTX 4090 on-demand minimum of $0.28, verifying both rates in the live table first.
Today's prices
USD/hr · 1× GPU · lowest on-demand price per provider
| Provider | L40S | RTX 4090 |
|---|---|---|
| Vast.ai | $0.80 | $0.28 |
| RunPod | $0.99 | $0.74 |
| DataCrunch | $1.37 | Not offered |
| Crusoe | $1.50 · Not reported | Not offered |
What your workload needs
Find your parameter count on the model's Hugging Face card. Serving maps to the inference rows, training to the fine-tuning rows.
| Workload | VRAM needed | L40S | RTX 4090 | Cheapest today |
|---|---|---|---|---|
| 70B Q4 inference | 42 GB | 1× $0.80/hr | 2× $0.28/hr | RTX 4090 ×2 → $0.56/hr (est.) |
| 70B FP16 inference | 168 GB | 4× $0.80/hr | 7× $0.28/hr | RTX 4090 ×7 → $1.96/hr (est.) |
| 70B QLoRA | 46 GB | 1× $0.80/hr | 2× $0.28/hr | RTX 4090 ×2 → $0.56/hr (est.) |
| 7B full fine-tune | 112 GB | 3× $0.80/hr | 5× $0.28/hr | RTX 4090 ×5 → $1.4/hr (est.) |
| 70B FP8 training | 154 GB | 4× $0.80/hr | 7× $0.28/hr | RTX 4090 ×7 → $1.96/hr (est.) |
| Downshift recommendation | 42 GB | 1× $0.80/hr | 2× $0.28/hr | L40S ×1 → $0.8/hr |
What the numbers say
L40S carries the higher on-demand minimum, with an A-to-B on-demand price ratio of 2.86. That makes RTX 4090 the default when the workload fits one card and hourly spend is the priority, while L40S earns its premium when additional memory avoids a multi-GPU configuration.
L40S’s published BF16 peak implies an A-to-B performance ratio of 2.19, but it is not measured workload throughput. Applied to the on-demand pricing comparison, that produces an effective cost-per-job ratio of 1.3 versus RTX 4090, suggesting L40S can complete equivalent compute for less when real-world utilization and software efficiency track the datasheet figures.
For RTX 4090, the baseline is FP8, BF16, or FP32 workloads within 24GB VRAM; the exception applies when model weights, KV cache, activations, or training state exceed that single-card ceiling. L40S supports the same precision choices with a larger VRAM ceiling, so choose it when that headroom keeps the workload on one GPU; otherwise RTX 4090 is the rational choice.
Before you rent
Marlin matches your workload requirements to the lowest-priced suitable GPU across major cloud providers.
Coverage is limited to the listed providers and published hardware specifications, while live availability and prices can change without notice. Workload costs and performance comparisons are modeled from VRAM formulas, on-demand rates, and datasheet peaks rather than measured end-to-end benchmarks. https://vast.ai/pricing · https://crusoe.ai/cloud/pricing · https://www.runpod.io/pricing · https://datacrunch.io/pricing · https://resources.nvidia.com/en-us-l40s/l40s-datasheet-28413 · https://www.nvidia.com/en-us/geforce/graphics-cards/40-series/rtx-4090/
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