GPT-OSS 20B (MoE) at FP8 (E4M3) needs 20.9 GB for its weights and 22.6 GB in total at 8K context with 8 concurrent users. That means it fits on a single TPU v5p (per-chip, 95GB). 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× TPU | 95 GB | 22.6 GB | 221.8 | 2662 | 291.5 ms | $0.4383 | ✓ |
| 2× TPU | 190 GB | 22.6 GB | 377.1 | 9050 | 161.2 ms | $0.2578 | ✓ |
| 4× TPU | 380 GB | 22.6 GB | 754.2 | 36200 | 95.6 ms | $0.1289 | ✓ |
| 8× TPU | 760 GB | 22.6 GB | 1508 | 144799 | 62.8 ms | $0.0645 | ✓ |
| Context | Concurrent users | KV per request | Fits? |
|---|---|---|---|
| 4K | 713 | 206.2 MB | ✓ fits |
| 8K | 362 | 412.3 MB | ✓ fits |
| 33K | 91 | 1.61 GB | ✓ fits |
| 66K | 45 | 3.22 GB | ✓ fits |
| 131K | 22 | 6.44 GB | ✓ fits |
| GPU | GPUs | Aggregate tok/s | Cost / 1M tok |
|---|---|---|---|
| RTX 5090 32GB | 1× | 5824 | $0.0238 |
| RTX 3090 24GB | 1× | 2472 | $0.0281 |
| RTX 4090 24GB | 1× | 3276 | $0.0339 |
| AMD MI300X 192GB | 1× | 17225 | $0.0403 |
| V100 SXM2 32GB | 1× | 2925 | $0.0475 |
| A100 40GB SXM4 | 1× | 5038 | $0.0496 |
Yes. GPT-OSS 20B (MoE) at FP8 (E4M3) needs 22.6 GB including the KV cache, and TPU v5p (per-chip, 95GB) has 95 GB — so it fits on a single GPU.
221.8 tokens/sec per stream and 2662 tok/s aggregate with continuous batching at 8 concurrent users. Time to first token is 291.5 ms, and inter-token latency is 4.5 ms.
$0.4383 per 1M output tokens at 1× TPU v5p (per-chip, 95GB) ($4.20/hr). That is the marginal hardware cost — add idle capacity, ops, and egress for the real figure.
20.9 GB for the weights at FP8 (E4M3), plus 1.6 GB of KV cache for 8 concurrent requests at 8K context — 22.6 GB total. Every extra concurrent user at long context costs more, so leave headroom.
It works. Compare $0.4383 per 1M tokens against the alternatives below — the cheapest option that fits the same workload is 4× RTX 3080 10GB at $0.006615, and the fastest is 1× Cerebras CS-3 (WSE-3) at 65000 tok/s.
Same formulas, your context length, concurrency, and quantisation.