Llama 3 8B at FP16 needs 16.1 GB for its weights and 24.6 GB in total at 8K context with 8 concurrent users. That means it fits on a single RTX 5090 32GB. 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× RTX | 32 GB | 24.6 GB | 72.53 | 870.3 | 2.55 s | $0.1596 | ✓ |
| 2× RTX | 64 GB | 24.6 GB | 123.3 | 2959 | 1.29 s | $0.0939 | ✓ |
| 4× RTX | 128 GB | 24.6 GB | 246.6 | 11837 | 660.5 ms | $0.0469 | ✓ |
| 8× RTX | 256 GB | 24.6 GB | 493.2 | 47346 | 345.3 ms | $0.0235 | ✓ |
| Context | Concurrent users | KV per request | Fits? |
|---|---|---|---|
| 4K | 29 | 549.8 MB | ✓ fits |
| 8K | 14 | 1.07 GB | ✓ fits |
| 33K | 3 | 4.29 GB | ✓ fits |
| 66K | 1 | 8.59 GB | ✓ fits |
| 131K | 0 | 17.18 GB | ✗ does not fit |
| GPU | GPUs | Aggregate tok/s | Cost / 1M tok |
|---|---|---|---|
| AMD MI300X 192GB | 1× | 2574 | $0.2698 |
| V100 SXM2 32GB | 1× | 437.1 | $0.3177 |
| A100 40GB SXM4 | 1× | 752.8 | $0.3321 |
| AMD MI325X 288GB | 1× | 2914 | $0.3336 |
| A100 80GB SXM4 | 1× | 971.4 | $0.3432 |
| Intel Gaudi 3 128GB | 1× | 1603 | $0.3466 |
Yes. Llama 3 8B at FP16 needs 24.6 GB including the KV cache, and RTX 5090 32GB has 32 GB — so it fits on a single GPU.
72.53 tokens/sec per stream and 870.3 tok/s aggregate with continuous batching at 8 concurrent users. Time to first token is 2.55 s, and inter-token latency is 13.8 ms.
$0.1596 per 1M output tokens at 1× RTX 5090 32GB ($0.5000/hr). That is the marginal hardware cost — add idle capacity, ops, and egress for the real figure.
16.1 GB for the weights at FP16, plus 8.6 GB of KV cache for 8 concurrent requests at 8K context — 24.6 GB total. Every extra concurrent user at long context costs more, so leave headroom.
It works. Compare $0.1596 per 1M tokens against the alternatives below — the cheapest option that fits the same workload is 4× RTX 3080 10GB at $0.0443, and the fastest is 1× Cerebras CS-3 (WSE-3) at 9714 tok/s.
Same formulas, your context length, concurrency, and quantisation.