RTX A6000 vs L40S
Both hold the same 48 GB, so the split is speed: the L40S has about 1.1× the memory bandwidth. Decode speed on a memory-bound workload scales with bandwidth, so that ratio is the number that matters once the model fits at all.
Specs side by side
| Spec | RTX A6000 | L40S |
|---|---|---|
| VRAM | 48 GB | 48 GB |
| Memory bandwidth | 768 GB/s | 864 GB/s |
| TDP | 300 W | 350 W |
| Models that fit (Q4_K_M) | 460 of 506 | 460 of 506 |
What the extra VRAM actually buys
Nothing, in model-fit terms: every model in our catalog that fits the L40S at Q4_K_M also fits the RTX A6000. The extra capacity goes to longer context, bigger batches and higher-precision quantization — not to a larger model tier.
Largest model each can run
At Q4_K_M the biggest fit in our catalog is Qwen 2 VL 72B Instruct (44.3 GB) on the RTX A6000, and Qwen 2 VL 72B Instruct (44.3 GB) on the L40S. Both figures are weights plus runtime overhead; KV cache for your context is extra.
Power and running cost
At 8 hours a day the RTX A6000 draws about 72 kWh a month against 84 kWh for the L40S — a difference of 12 kWh. Multiply by your own tariff; we do not assume one. Board TDP is the rated figure, not measured draw.
FAQ
RTX A6000 vs L40S: which should I buy for local AI?
The L40S fits 460 of the 506 models in our catalog at Q4_K_M against 460 for the RTX A6000, and has about 1.1× the memory bandwidth, which is what sets decode speed once a model fits. If the models you run already fit the RTX A6000, the extra spend buys context length and speed, not a new model tier.
Is the L40S faster than the RTX A6000?
On memory-bound decoding, yes — roughly 1.1× the throughput, since token generation scales with memory bandwidth (864 GB/s vs 768 GB/s). This is an upper bound from bandwidth alone, not a measured benchmark.
How much more VRAM does the L40S have?
Neither has more — both carry 48 GB. No model in our catalog needs the difference at Q4_K_M.
Need a third card in the mix? The interactive compare tool lines up any three. To size KV cache for your context length, use the GPU Memory Calculator.
Related matchups
Other head-to-heads involving these cards:
RTX 4090 vs RTX A6000RTX 5090 vs RTX A6000A100 40GB vs L40SRTX 5090 vs L40SA100 40GB vs RTX A6000
New to sizing? What VRAM is and why bandwidth sets decode speed cover the basics, and quantization explains the formats in the table above. Common mistakes when sizing VRAM lists the traps.