Speed test matrix
gpt-oss-20b on RTX 3090 24GB
vllm · 0.32.0 · MXFP45 contexts (0–120K) × 8 concurrency levels (1–128) · prefill at 8K, 16K, 32K, 64K, 120K
Hardware
- Type
- Discrete GPU
- GPU
- RTX 3090
- VRAM
- 24 GB
- CPU
- AMD Ryzen 9 7900X (12C)
- RAM
- 32 GB
- OS
- Ubuntu 24.04.5
Engine
- Engine
- vllm
- Version
- 0.32.0
- Quantization
- MXFP4
- Backend
- cuda
- Repository
- github.com/vllm-project/vllm
- Build
- vllm/vllm-openai:v0.32.0-x86_64
Run
- Served model
- bench
- Revision
- main
- Benchmark tool
- llm-inference-bench v0.8.0
- Decode test
- Fixed duration
- Prefill mode
- Measured during decode warm-up
- Time per measurement
- 30 s
- Max output
- 8,192 tokens
Launch command
# Untuned out-of-the-box baseline. Spec decode: none # 1x RTX 3090 24GB (Zagitta/gpu-unlock), 350 W limit (VBIOS max), PCIe Gen4 x16 | AMD Ryzen 9 7900X 12C | 32 GB DDR5 | Ubuntu 24.04.5, NVIDIA driver 595.99.02 vllm serve openai/gpt-oss-20b --max-model-len 131072 --gpu-memory-utilization 0.94 --max-num-seqs 128 --enable-prefix-caching --trust-remote-code
Prefill
prompt tok/s by context length8K context9,483860 ms TTFT
16K context7,5862,122 ms TTFT
32K context5,3955,931 ms TTFT
64K context3,38018,871 ms TTFT
120K context2,07757,490 ms TTFT
Sustained decode
total tok/s · rows are context length, columns are simultaneous requests| Context | 1 | 2 | 4 | 8 | 16 | 32 | 64 | 128 |
|---|---|---|---|---|---|---|---|---|
| 0 | 165.640 ms TTFT | Looped | 423.850 ms TTFT | 609.656 ms TTFT | 909.973 ms TTFT | 1,766.593 ms TTFT | Over capacity | Over capacity |
| 16K | 145.153 ms TTFT | 182.881 ms TTFT | 342.7114 ms TTFT | 296.7167 ms TTFT | Over capacity | Over capacity | Over capacity | Over capacity |
| 32K | 137.075 ms TTFT | 212.0120 ms TTFT | 297.2181 ms TTFT | Over capacity | Over capacity | Over capacity | Over capacity | Over capacity |
| 64K | 106.9111 ms TTFT | 164.5194 ms TTFT | Over capacity | Over capacity | Over capacity | Over capacity | Over capacity | Over capacity |
| 120K | 81.9184 ms TTFT | 125.9266 ms TTFT | Over capacity | Over capacity | Over capacity | Over capacity | Over capacity | Over capacity |
Looped: the model kept repeating the same text, so the benchmark discarded this measurement. Over capacity: not run because this many requests at this context would exceed the server's KV cache.
TTFT is measured after the benchmark warms the server's prompt cache, so it mostly excludes prefill.
All measurements
Latencies are medians. Total tok/s is output across all simultaneous requests.| Phase | Context | Requests at once | Status | Total tok/s | Per request tok/s | TTFT | Time between tokens | Average active requests | Completed requests | Output tokens | Measured for |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Prefill | 8K | 1 | Valid | 9,483.0 | — | 860 ms | — | — | 1 | — | — |
| Prefill | 16K | 1 | Valid | 7,586.0 | — | 2,122 ms | — | — | 1 | — | — |
| Prefill | 32K | 1 | Valid | 5,395.0 | — | 5,931 ms | — | — | 1 | — | — |
| Prefill | 64K | 1 | Valid | 3,380.0 | — | 18,871 ms | — | — | 1 | — | — |
| Prefill | 120K | 1 | Valid | 2,077.0 | — | 57,490 ms | — | — | 1 | — | — |
| Sustained decode | 0 | 1 | Valid | 165.6 | 166.8 | 40 ms | 6.0 ms | 1.0 | 0 | 4,968 | 30.0 s |
| Sustained decode | 0 | 2 | Looped | — | — | — | — | — | 0 | 0 | — |
| Sustained decode | 0 | 4 | Valid | 423.8 | 106.4 | 50 ms | 9.4 ms | 4.0 | 0 | 12,713 | 30.0 s |
| Sustained decode | 0 | 8 | Valid | 609.6 | 83.5 | 56 ms | 12.0 ms | 8.0 | 0 | 18,287 | 30.0 s |
| Sustained decode | 0 | 16 | Valid | 909.9 | 67.1 | 73 ms | 14.9 ms | 16.0 | 0 | 27,287 | 30.0 s |
| Sustained decode | 0 | 32 | Valid | 1,766.5 | 60.2 | 93 ms | 16.6 ms | 32.0 | 0 | 52,982 | 30.0 s |
| Sustained decode | 0 | 64 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 0 | 128 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 16K | 1 | Valid | 145.1 | 145.5 | 53 ms | 6.9 ms | 1.0 | 0 | 4,353 | 30.0 s |
| Sustained decode | 16K | 2 | Valid | 182.8 | 114.6 | 81 ms | 8.7 ms | 2.0 | 0 | 5,477 | 30.0 s |
| Sustained decode | 16K | 4 | Valid | 342.7 | 86.3 | 114 ms | 11.6 ms | 4.0 | 0 | 10,279 | 30.0 s |
| Sustained decode | 16K | 8 | Valid | 296.7 | 66.5 | 167 ms | 15.0 ms | 8.0 | 0 | 8,899 | 30.0 s |
| Sustained decode | 16K | 16 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 16K | 32 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 16K | 64 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 16K | 128 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 32K | 1 | Valid | 137.0 | 130.1 | 75 ms | 7.7 ms | 1.0 | 0 | 4,094 | 29.9 s |
| Sustained decode | 32K | 2 | Valid | 212.0 | 101.3 | 120 ms | 9.9 ms | 2.0 | 0 | 6,361 | 30.0 s |
| Sustained decode | 32K | 4 | Valid | 297.2 | 74.3 | 181 ms | 13.5 ms | 4.0 | 0 | 8,915 | 30.0 s |
| Sustained decode | 32K | 8 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 32K | 16 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 32K | 32 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 32K | 64 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 32K | 128 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 64K | 1 | Valid | 106.9 | 107.0 | 111 ms | 9.3 ms | 1.0 | 0 | 3,206 | 30.0 s |
| Sustained decode | 64K | 2 | Valid | 164.5 | 84.1 | 194 ms | 11.9 ms | 2.0 | 0 | 4,933 | 30.0 s |
| Sustained decode | 64K | 4 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 64K | 8 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 64K | 16 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 64K | 32 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 64K | 64 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 64K | 128 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 120K | 1 | Valid | 81.9 | 82.1 | 184 ms | 12.2 ms | 1.0 | 0 | 2,458 | 30.0 s |
| Sustained decode | 120K | 2 | Valid | 125.9 | 64.3 | 266 ms | 15.5 ms | 2.0 | 0 | 3,776 | 30.0 s |
| Sustained decode | 120K | 4 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 120K | 8 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 120K | 16 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 120K | 32 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 120K | 64 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 120K | 128 | Over capacity | — | — | — | — | — | — | — | — |
Looped: the model kept repeating the same text, so the benchmark discarded this measurement. Over capacity: not run because this many requests at this context would exceed the server's KV cache.