Qwen3.8 27B (VLM) at FP8 (E4M3) needs 27.8 GB for its weights and 33.3 GB in total at 8K context with 8 concurrent users. That means it fits on a single Mac M2 Ultra (192GB unified). 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× Mac | 192 GB | 33.3 GB | 28.08 | 243.0 | 33.78 s | — | ✓ |
| 2× Mac | 384 GB | 33.3 GB | 47.73 | 971.9 | 16.91 s | — | ✓ |
| 4× Mac | 768 GB | 33.3 GB | 95.46 | 3888 | 8.47 s | — | ✓ |
| 8× Mac | 1536 GB | 33.3 GB | 190.9 | 15550 | 4.25 s | — | ✓ |
| Context | Concurrent users | KV per request | Fits? |
|---|---|---|---|
| 4K | 391 | 1.07 GB | ✓ fits |
| 8K | 238 | 2.15 GB | ✓ fits |
| 33K | 71 | 8.59 GB | ✓ fits |
| 66K | 36 | 17.18 GB | ✓ fits |
| 131K | 18 | 34.36 GB | ✓ fits |
| GPU | GPUs | Aggregate tok/s | Cost / 1M tok |
|---|---|---|---|
| RTX 5090 32GB | 2× | 2566 | $0.1083 |
| AMD MI300X 192GB | 1× | 2232 | $0.3111 |
| A100 40GB SXM4 | 1× | 652.8 | $0.3830 |
| AMD MI325X 288GB | 1× | 2527 | $0.3847 |
| A100 80GB SXM4 | 1× | 842.3 | $0.3957 |
| Intel Gaudi 3 128GB | 1× | 1390 | $0.3997 |
Yes. Qwen3.8 27B (VLM) at FP8 (E4M3) needs 33.3 GB including the KV cache, and Mac M2 Ultra (192GB unified) has 192 GB — so it fits on a single GPU.
28.08 tokens/sec per stream and 243.0 tok/s aggregate with continuous batching at 8 concurrent users. Time to first token is 33.78 s, and inter-token latency is 35.6 ms.
— per 1M output tokens at 1× Mac M2 Ultra (192GB unified). That is the marginal hardware cost — add idle capacity, ops, and egress for the real figure.
27.8 GB for the weights at FP8 (E4M3), plus 5.5 GB of KV cache for 8 concurrent requests at 8K context — 33.3 GB total. Every extra concurrent user at long context costs more, so leave headroom.
It works. Compare — per 1M tokens against the alternatives below — the cheapest option that fits the same workload is 4× RTX 3080 10GB at $0.0511, and the fastest is 1× Cerebras CS-3 (WSE-3) at 8423 tok/s.
Same formulas, your context length, concurrency, and quantisation.