Llama 2 7B at FP16 needs 13.5 GB for its weights and 47.8 GB in total at 8K context with 8 concurrent users. That means it needs 2× RTX 5090 32GB. Every figure is computed by tokcalc's open-source capacity model.
RTX 5090 32GB has no NVLink, so 2-way tensor parallelism runs over PCIe. tokcalc applies a flat 0.85× multi-GPU efficiency factor for this, which is realistic for NVLink-equipped datacenter cards but optimistic for PCIe scale-out — treat the throughput and cost figures for this configuration as an upper bound, and measure before committing.
| GPUs | Total VRAM | VRAM needed | Decode tok/s | Aggregate tok/s | TTFT | Cost / 1M tok | Fits? |
|---|---|---|---|---|---|---|---|
| 1× RTX | 32 GB | 47.8 GB | 0.000 | 0.000 | — | — | ✗ |
| 2× RTX | 64 GB | 47.8 GB | 146.9 | 3526 | 1.09 s | $0.0788 | ✓ |
| 4× RTX | 128 GB | 47.8 GB | 293.8 | 14102 | 559.3 ms | $0.0394 | ✓ |
| 8× RTX | 256 GB | 47.8 GB | 587.6 | 56408 | 294.6 ms | $0.0197 | ✓ |
| Context | Concurrent users | KV per request | Fits? |
|---|---|---|---|
| 4K | 23 | 2.15 GB | ✓ fits |
| 8K | 11 | 4.29 GB | ✓ fits |
| 33K | 2 | 17.18 GB | ✓ fits |
| 66K | 1 | 34.36 GB | ✓ fits |
| 131K | 0 | 68.72 GB | ✗ does not fit |
| GPU | GPUs | Aggregate tok/s | Cost / 1M tok |
|---|---|---|---|
| AMD MI300X 192GB | 1× | 3067 | $0.2264 |
| AMD MI325X 288GB | 1× | 3472 | $0.2800 |
| A100 80GB SXM4 | 1× | 1157 | $0.2880 |
| Intel Gaudi 3 128GB | 1× | 1909 | $0.2909 |
| H100 SXM5 80GB | 1× | 1938 | $0.3583 |
| B200 SXM 192GB | 1× | 4629 | $0.3600 |
Yes, but it needs 2× RTX 5090 32GB. At FP16 the total footprint is 47.8 GB (13.5 GB of weights plus 34.4 GB of KV cache at 8K × 8 concurrent users), against 64 GB of available VRAM across 2 GPUs.
146.9 tokens/sec per stream and 3526 tok/s aggregate with continuous batching at 8 concurrent users. Time to first token is 1.09 s, and inter-token latency is 6.8 ms.
$0.0788 per 1M output tokens at 2× RTX 5090 32GB ($0.5000/hr). That is the marginal hardware cost — add idle capacity, ops, and egress for the real figure.
13.5 GB for the weights at FP16, plus 34.4 GB of KV cache for 8 concurrent requests at 8K context — 47.8 GB total. Every extra concurrent user at long context costs more, so leave headroom.
It works. Compare $0.0788 per 1M tokens against the alternatives below — the cheapest option that fits the same workload is 8× RTX 3080 10GB at $0.0186, and the fastest is 2× Cerebras CS-3 (WSE-3) at 39347 tok/s.
Same formulas, your context length, concurrency, and quantisation.