Speed test matrix
gemma-4-12B-it-qat-w4a16-ct on RTX 3090 24GB
vllm · 0.32.0 · W4A166 contexts (0–248K) × 8 concurrency levels (1–128) · prefill at 8K, 16K, 32K, 64K, 128K
Hardware
- Type
- Discrete GPU
- GPU
- RTX 3090
- VRAM
- 24 GB
- CPU
- Intel Core i7-9700K (8C)
- RAM
- 32 GB
- OS
- Ubuntu 24.04.5
Engine
- Engine
- vllm
- Version
- 0.32.0
- Quantization
- W4A16
- 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. KV cache: int4_per_token_head # 1x RTX 3090 24GB (Zagitta/gpu-unlock), 420 W limit, PCIe Gen3 x16 | Intel Core i7-9700K 8C | 32 GB DDR4 | Ubuntu 24.04.5, NVIDIA driver 580.178.04 vllm serve google/gemma-4-12B-it-qat-w4a16-ct --max-model-len 262144 --gpu-memory-utilization 0.94 --max-num-seqs 128 --enable-prefix-caching --trust-remote-code --language-model-only --kv-cache-dtype int4_per_token_head --attention-backend TRITON_ATTN
Prefill
prompt tok/s by context length8K context3,0122,660 ms TTFT
16K context2,6426,009 ms TTFT
32K context2,17014,559 ms TTFT
64K context1,60639,246 ms TTFT
128K context1,056119,243 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 | 68.345 ms TTFT | 129.550 ms TTFT | 235.083 ms TTFT | 400.988 ms TTFT | 620.1118 ms TTFT | 949.5187 ms TTFT | 1,397.0341 ms TTFT | Over capacity |
| 16K | 49.498 ms TTFT | Looped | Looped | Looped | Looped | Over capacity | Over capacity | Over capacity |
| 32K | 43.2227 ms TTFT | Looped | 160.8344 ms TTFT | Looped | Over capacity | Over capacity | Over capacity | Over capacity |
| 64K | 37.4346 ms TTFT | 74.2467 ms TTFT | 136.9684 ms TTFT | Looped | Over capacity | Over capacity | Over capacity | Over capacity |
| 128K | 29.5784 ms TTFT | 58.9968 ms TTFT | 104.91,372 ms TTFT | Over capacity | Over capacity | Over capacity | Over capacity | Over capacity |
| 248K | 20.6Requests queued1,561 ms TTFT | 40.4Requests queued2,026 ms TTFT | Over capacity | Over capacity | Over capacity | Over capacity | Over capacity | Over capacity |
Requests queued: the server could not run all requests at once, so some waited in a queue. 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 | 3,012.0 | — | 2,660 ms | — | — | 1 | — | — |
| Prefill | 16K | 1 | Valid | 2,642.0 | — | 6,009 ms | — | — | 1 | — | — |
| Prefill | 32K | 1 | Valid | 2,170.0 | — | 14,559 ms | — | — | 1 | — | — |
| Prefill | 64K | 1 | Valid | 1,606.0 | — | 39,246 ms | — | — | 1 | — | — |
| Prefill | 128K | 1 | Valid | 1,056.0 | — | 119,243 ms | — | — | 1 | — | — |
| Sustained decode | 0 | 1 | Valid | 68.3 | 68.8 | 45 ms | 14.5 ms | 1.0 | 0 | 2,048 | 30.0 s |
| Sustained decode | 0 | 2 | Valid | 129.5 | 65.6 | 50 ms | 15.2 ms | 2.0 | 0 | 3,884 | 30.0 s |
| Sustained decode | 0 | 4 | Valid | 235.0 | 60.1 | 83 ms | 16.7 ms | 4.0 | 0 | 7,048 | 30.0 s |
| Sustained decode | 0 | 8 | Valid | 400.9 | 51.9 | 88 ms | 19.3 ms | 8.0 | 0 | 12,024 | 30.0 s |
| Sustained decode | 0 | 16 | Valid | 620.1 | 41.1 | 118 ms | 24.3 ms | 16.0 | 0 | 18,592 | 30.0 s |
| Sustained decode | 0 | 32 | Valid | 949.5 | 32.4 | 187 ms | 30.9 ms | 32.0 | 0 | 28,480 | 30.0 s |
| Sustained decode | 0 | 64 | Valid | 1,397.0 | 23.6 | 341 ms | 42.3 ms | 64.0 | 0 | 41,920 | 30.0 s |
| Sustained decode | 0 | 128 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 16K | 1 | Valid | 49.4 | 49.8 | 98 ms | 20.1 ms | 1.0 | 0 | 1,482 | 30.0 s |
| Sustained decode | 16K | 2 | Looped | — | — | — | — | — | 0 | 0 | — |
| Sustained decode | 16K | 4 | Looped | — | — | — | — | — | 0 | 0 | — |
| Sustained decode | 16K | 8 | Looped | — | — | — | — | — | 0 | 0 | — |
| Sustained decode | 16K | 16 | Looped | — | — | — | — | — | 0 | 0 | — |
| Sustained decode | 16K | 32 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 16K | 64 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 16K | 128 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 32K | 1 | Valid | 43.2 | 43.2 | 227 ms | 23.2 ms | 1.0 | 0 | 1,294 | 30.0 s |
| Sustained decode | 32K | 2 | Looped | — | — | — | — | — | 0 | 0 | — |
| Sustained decode | 32K | 4 | Valid | 160.8 | 40.2 | 344 ms | 24.9 ms | 4.0 | 0 | 4,820 | 30.0 s |
| Sustained decode | 32K | 8 | Looped | — | — | — | — | — | 0 | 0 | — |
| 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 | 37.4 | 37.5 | 346 ms | 26.6 ms | 1.0 | 0 | 1,123 | 30.0 s |
| Sustained decode | 64K | 2 | Valid | 74.2 | 37.1 | 467 ms | 26.9 ms | 2.0 | 0 | 2,224 | 30.0 s |
| Sustained decode | 64K | 4 | Valid | 136.9 | 34.2 | 684 ms | 29.2 ms | 4.0 | 0 | 4,104 | 30.0 s |
| Sustained decode | 64K | 8 | Looped | — | — | — | — | — | 0 | 0 | — |
| 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 | 128K | 1 | Valid | 29.5 | 29.6 | 784 ms | 33.8 ms | 1.0 | 0 | 885 | 30.0 s |
| Sustained decode | 128K | 2 | Valid | 58.9 | 29.5 | 968 ms | 33.9 ms | 2.0 | 0 | 1,767 | 30.0 s |
| Sustained decode | 128K | 4 | Valid | 104.9 | 26.1 | 1,372 ms | 38.2 ms | 4.0 | 0 | 3,148 | 30.0 s |
| Sustained decode | 128K | 8 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 128K | 16 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 128K | 32 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 128K | 64 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 128K | 128 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 248K | 1 | Requests queued | 20.6 | 21.4 | 1,561 ms | 46.8 ms | 1.0 | 0 | 619 | 30.0 s |
| Sustained decode | 248K | 2 | Requests queued | 40.4 | 21.3 | 2,026 ms | 47.0 ms | 1.9 | 0 | 1,212 | 30.0 s |
| Sustained decode | 248K | 4 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 248K | 8 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 248K | 16 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 248K | 32 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 248K | 64 | Over capacity | — | — | — | — | — | — | — | — |
| Sustained decode | 248K | 128 | Over capacity | — | — | — | — | — | — | — | — |
Requests queued: the server could not run all requests at once, so some waited in a queue. 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.