Qwen 3 4B at FP16 needs 8.0 GB for its weights and 17.7 GB in total at 8K context with 8 concurrent users. That means it fits on a single L4 24GB. Every figure is computed by tokcalc's open-source capacity model.
| GPUs | Total VRAM | VRAM needed | Decode tok/s | Aggregate tok/s | TTFT | Cost / 1M tok | Fits? |
|---|---|---|---|---|---|---|---|
| 1× L4 | 24 GB | 17.7 GB | 24.38 | 292.5 | 4.40 s | $0.3799 | ✓ |
| 2× L4 | 48 GB | 17.7 GB | 41.44 | 994.5 | 2.22 s | $0.2235 | ✓ |
| 4× L4 | 96 GB | 17.7 GB | 82.88 | 3978 | 1.12 s | $0.1117 | ✓ |
| 8× L4 | 192 GB | 17.7 GB | 165.8 | 15912 | 576.8 ms | $0.0559 | ✓ |
| Context | Concurrent users | KV per request | Fits? |
|---|---|---|---|
| 4K | 26 | 618.5 MB | ✓ fits |
| 8K | 13 | 1.21 GB | ✓ fits |
| 33K | 3 | 4.83 GB | ✓ fits |
| 66K | 1 | 9.66 GB | ✓ fits |
| 131K | 0 | 19.33 GB | ✗ does not fit |
| GPU | GPUs | Aggregate tok/s | Cost / 1M tok |
|---|---|---|---|
| RTX 3090 24GB | 1× | 912.6 | $0.0761 |
| RTX 5090 32GB | 1× | 1747 | $0.0795 |
| RTX 4090 24GB | 1× | 982.8 | $0.1131 |
| AMD MI300X 192GB | 1× | 5168 | $0.1344 |
| V100 SXM2 32GB | 1× | 877.5 | $0.1583 |
| A100 40GB SXM4 | 1× | 1511 | $0.1654 |
Yes. Qwen 3 4B at FP16 needs 17.7 GB including the KV cache, and L4 24GB has 24 GB — so it fits on a single GPU.
24.38 tokens/sec per stream and 292.5 tok/s aggregate with continuous batching at 8 concurrent users. Time to first token is 4.40 s, and inter-token latency is 41.0 ms.
$0.3799 per 1M output tokens at 1× L4 24GB ($0.4000/hr). That is the marginal hardware cost — add idle capacity, ops, and egress for the real figure.
8.0 GB for the weights at FP16, plus 9.7 GB of KV cache for 8 concurrent requests at 8K context — 17.7 GB total. Every extra concurrent user at long context costs more, so leave headroom.
It works. Compare $0.3799 per 1M tokens against the alternatives below — the cheapest option that fits the same workload is 2× RTX 3080 10GB at $0.0441, and the fastest is 1× Cerebras CS-3 (WSE-3) at 19500 tok/s.
Same formulas, your context length, concurrency, and quantisation.