Speed test matrix

Qwen3.5-9B-AWQ-4bit on RTX 3090 24GB

vllm · 0.32.0 · W4A16 g326 contexts (0–248K) × 8 concurrency levels (1–128) · prefill at 8K, 16K, 32K, 64K, 128K

by @Sandbergllm-inference-bench v0.8.0Measured Nov 1, 2026, 16:04 UTC

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 g32
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 cyankiwi/Qwen3.5-9B-AWQ-4bit --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 length

8K context6,1111,340 ms TTFT

16K context5,2993,061 ms TTFT

32K context4,1867,715 ms TTFT

64K context2,95421,804 ms TTFT

128K context1,86069,190 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	112.039 ms TTFT	209.344 ms TTFT	404.583 ms TTFT	774.8131 ms TTFT	1,325.6284 ms TTFT	2,089.1386 ms TTFT	2,795.8747 ms TTFT	3,300.3975 ms TTFT
16K	97.9487 ms TTFT	180.2714 ms TTFT	308.71,168 ms TTFT	531.32,082 ms TTFT	796.93,934 ms TTFT	1,049.87,673 ms TTFT	1,201.415,380 ms TTFT	Over capacity
32K	86.8614 ms TTFT	158.2891 ms TTFT	247.21,439 ms TTFT	401.32,542 ms TTFT	564.84,757 ms TTFT	698.99,293 ms TTFT	Over capacity	Over capacity
64K	70.8688 ms TTFT	126.9941 ms TTFT	179.61,484 ms TTFT	271.02,551 ms TTFT	358.24,740 ms TTFT	Over capacity	Over capacity	Over capacity
128K	51.51,933 ms TTFT	90.92,744 ms TTFT	115.84,437 ms TTFT	163.37,774 ms TTFT	Over capacity	Over capacity	Over capacity	Over capacity
248K	31.3Requests queued3,006 ms TTFT	59.44,216 ms TTFT	69.36,668 ms TTFT	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. 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	6,111.0	—	1,340 ms	—	—	1	—	—
Prefill	16K	1	Valid	5,299.0	—	3,061 ms	—	—	1	—	—
Prefill	32K	1	Valid	4,186.0	—	7,715 ms	—	—	1	—	—
Prefill	64K	1	Valid	2,954.0	—	21,804 ms	—	—	1	—	—
Prefill	128K	1	Valid	1,860.0	—	69,190 ms	—	—	1	—	—
Sustained decode	0	1	Valid	112.0	112.4	39 ms	8.9 ms	1.0	0	3,360	30.0 s
Sustained decode	0	2	Valid	209.3	105.0	44 ms	9.5 ms	2.0	0	6,278	30.0 s
Sustained decode	0	4	Valid	404.5	101.6	83 ms	9.8 ms	4.0	0	12,135	30.0 s
Sustained decode	0	8	Valid	774.8	97.6	131 ms	10.2 ms	8.0	0	23,240	30.0 s
Sustained decode	0	16	Valid	1,325.6	83.8	284 ms	11.9 ms	16.0	0	39,774	30.0 s
Sustained decode	0	32	Valid	2,089.1	66.1	386 ms	15.1 ms	32.0	0	62,656	30.0 s
Sustained decode	0	64	Valid	2,795.8	44.1	747 ms	22.7 ms	64.0	0	83,886	30.0 s
Sustained decode	0	128	Valid	3,300.3	25.5	975 ms	39.2 ms	128.0	0	99,027	30.0 s
Sustained decode	16K	1	Valid	97.9	98.1	487 ms	10.2 ms	1.0	0	2,938	30.0 s
Sustained decode	16K	2	Valid	180.2	89.7	714 ms	11.2 ms	2.0	0	5,406	30.0 s
Sustained decode	16K	4	Valid	308.7	75.9	1,168 ms	13.2 ms	4.0	0	9,260	30.0 s
Sustained decode	16K	8	Valid	531.3	63.8	2,082 ms	15.7 ms	8.0	0	15,936	30.0 s
Sustained decode	16K	16	Valid	796.9	45.6	3,934 ms	21.9 ms	16.0	0	23,904	30.0 s
Sustained decode	16K	32	Valid	1,049.8	27.7	7,673 ms	36.1 ms	32.0	0	31,496	30.0 s
Sustained decode	16K	64	Valid	1,201.4	13.9	15,380 ms	71.8 ms	64.0	0	36,032	30.0 s
Sustained decode	16K	128	Over capacity	—	—	—	—	—	—	—	—
Sustained decode	32K	1	Valid	86.8	86.9	614 ms	11.5 ms	1.0	0	2,603	30.0 s
Sustained decode	32K	2	Valid	158.2	78.6	891 ms	12.7 ms	2.0	0	4,744	30.0 s
Sustained decode	32K	4	Valid	247.2	60.5	1,439 ms	16.5 ms	4.0	0	7,416	30.0 s
Sustained decode	32K	8	Valid	401.3	47.7	2,542 ms	21.0 ms	8.0	0	12,032	30.0 s
Sustained decode	32K	16	Valid	564.8	31.8	4,757 ms	31.4 ms	16.0	0	16,944	30.0 s
Sustained decode	32K	32	Valid	698.9	17.8	9,293 ms	56.0 ms	32.0	0	20,960	30.0 s
Sustained decode	32K	64	Over capacity	—	—	—	—	—	—	—	—
Sustained decode	32K	128	Over capacity	—	—	—	—	—	—	—	—
Sustained decode	64K	1	Valid	70.8	70.9	688 ms	14.1 ms	1.0	0	2,123	30.0 s
Sustained decode	64K	2	Valid	126.9	63.1	941 ms	15.9 ms	2.0	0	3,808	30.0 s
Sustained decode	64K	4	Valid	179.6	44.0	1,484 ms	22.7 ms	4.0	0	5,387	30.0 s
Sustained decode	64K	8	Valid	271.0	32.3	2,551 ms	30.9 ms	8.0	0	8,128	30.0 s
Sustained decode	64K	16	Valid	358.2	20.3	4,740 ms	49.2 ms	16.0	0	10,736	30.0 s
Sustained decode	64K	32	Over capacity	—	—	—	—	—	—	—	—
Sustained decode	64K	64	Over capacity	—	—	—	—	—	—	—	—
Sustained decode	64K	128	Over capacity	—	—	—	—	—	—	—	—
Sustained decode	128K	1	Valid	51.5	51.6	1,933 ms	19.4 ms	1.0	0	1,543	30.0 s
Sustained decode	128K	2	Valid	90.9	44.5	2,744 ms	22.5 ms	2.0	0	2,728	30.0 s
Sustained decode	128K	4	Valid	115.8	27.1	4,437 ms	36.9 ms	4.0	0	3,472	30.0 s
Sustained decode	128K	8	Valid	163.3	17.6	7,774 ms	57.0 ms	8.0	0	4,896	30.0 s
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	31.3	34.1	3,006 ms	29.3 ms	0.9	0	939	30.0 s
Sustained decode	248K	2	Valid	59.4	28.8	4,216 ms	34.7 ms	2.0	0	1,782	30.0 s
Sustained decode	248K	4	Valid	69.3	15.7	6,668 ms	63.6 ms	4.0	0	2,076	29.9 s
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. Over capacity: not run because this many requests at this context would exceed the server's KV cache.