Mixtral 8x7B (MoE) at FP8 (E4M3) needs 46.7 GB for its weights and 55.3 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 | 55.3 GB | 0.000 | 0.000 | — | — | ✗ |
| 2× RTX | 64 GB | 55.3 GB | 230.3 | 5526 | 2.05 s | $0.0503 | ✓ |
| 4× RTX | 128 GB | 55.3 GB | 460.5 | 22104 | 1.04 s | $0.0251 | ✓ |
| 8× RTX | 256 GB | 55.3 GB | 921.0 | 88416 | 534.3 ms | $0.0126 | ✓ |
| Context | Concurrent users | KV per request | Fits? |
|---|---|---|---|
| 4K | 32 | 549.8 MB | ✓ fits |
| 8K | 16 | 1.07 GB | ✓ fits |
| 33K | 4 | 4.29 GB | ✓ fits |
| 66K | 2 | 8.59 GB | ✓ fits |
| 131K | 1 | 17.18 GB | ✓ fits |
| GPU | GPUs | Aggregate tok/s | Cost / 1M tok |
|---|---|---|---|
| AMD MI300X 192GB | 1× | 4807 | $0.1445 |
| L40S 48GB | 2× | 2664 | $0.1460 |
| AMD MI325X 288GB | 1× | 5442 | $0.1787 |
| A100 80GB SXM4 | 1× | 1814 | $0.1838 |
| Intel Gaudi 3 128GB | 1× | 2993 | $0.1856 |
| H100 SXM5 80GB | 1× | 3038 | $0.2286 |
Yes, but it needs 2× RTX 5090 32GB. At FP8 (E4M3) the total footprint is 55.3 GB (46.7 GB of weights plus 8.6 GB of KV cache at 8K × 8 concurrent users), against 64 GB of available VRAM across 2 GPUs.
230.3 tokens/sec per stream and 5526 tok/s aggregate with continuous batching at 8 concurrent users. Time to first token is 2.05 s, and inter-token latency is 4.3 ms.
$0.0503 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.
46.7 GB for the weights at FP8 (E4M3), plus 8.6 GB of KV cache for 8 concurrent requests at 8K context — 55.3 GB total. Every extra concurrent user at long context costs more, so leave headroom.
It works. Compare $0.0503 per 1M tokens against the alternatives below — the cheapest option that fits the same workload is 8× RTX 3080 10GB at $0.0119, and the fastest is 2× Cerebras CS-3 (WSE-3) at 61674 tok/s.
Same formulas, your context length, concurrency, and quantisation.