Gemma 2 9B at FP16 needs 18.0 GB for its weights and 40.5 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 | 40.5 GB | 0.000 | 0.000 | — | — | ✗ |
| 2× RTX | 64 GB | 40.5 GB | 110.0 | 2640 | 1.44 s | $0.1052 | ✓ |
| 4× RTX | 128 GB | 40.5 GB | 220.0 | 10561 | 736.7 ms | $0.0526 | ✓ |
| 8× RTX | 256 GB | 40.5 GB | 440.0 | 42243 | 383.4 ms | $0.0263 | ✓ |
| Context | Concurrent users | KV per request | Fits? |
|---|---|---|---|
| 4K | 32 | 1.41 GB | ✓ fits |
| 8K | 16 | 2.82 GB | ✓ fits |
| 33K | 4 | 11.27 GB | ✓ fits |
| 66K | 2 | 22.55 GB | ✓ fits |
| 131K | 1 | 45.10 GB | ✓ fits |
| GPU | GPUs | Aggregate tok/s | Cost / 1M tok |
|---|---|---|---|
| AMD MI300X 192GB | 1× | 2297 | $0.3024 |
| AMD MI325X 288GB | 1× | 2600 | $0.3739 |
| A100 80GB SXM4 | 1× | 866.7 | $0.3846 |
| Intel Gaudi 3 128GB | 1× | 1430 | $0.3885 |
| H100 SXM5 80GB | 1× | 1452 | $0.4784 |
| B200 SXM 192GB | 1× | 3467 | $0.4808 |
Yes, but it needs 2× RTX 5090 32GB. At FP16 the total footprint is 40.5 GB (18.0 GB of weights plus 22.5 GB of KV cache at 8K × 8 concurrent users), against 64 GB of available VRAM across 2 GPUs.
110.0 tokens/sec per stream and 2640 tok/s aggregate with continuous batching at 8 concurrent users. Time to first token is 1.44 s, and inter-token latency is 9.1 ms.
$0.1052 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.
18.0 GB for the weights at FP16, plus 22.5 GB of KV cache for 8 concurrent requests at 8K context — 40.5 GB total. Every extra concurrent user at long context costs more, so leave headroom.
It works. Compare $0.1052 per 1M tokens against the alternatives below — the cheapest option that fits the same workload is 8× RTX 3080 10GB at $0.0248, and the fastest is 8× RTX 3080 10GB at 17916 tok/s.
Same formulas, your context length, concurrency, and quantisation.