Can RTX 4090 24GB run Qwen3.5 9B?
Measured results for Qwen3.5 9B (9.65B dense) on RTX 4090 24GB, plus what fits and the commands to run it.
Short answer
Yes. Qwen3.5 9B Q8_0 fits fully on RTX 4090 24GB at 16k context, using 10.1 of 23.0 GB usable, and generates about 95.1 tokens/s in our own run. As the context fills it slows down: 90 tok/s with 16k tokens already in context (95% of the empty-context speed), measured. For Q8_0, our bandwidth-only estimate was ~58 tok/s against a measured median of ~95 (39% too pessimistic).
Measured generation speed by quantization
| Quant | Generation tok/s | Range | Prompt tok/s | Runs | Origin |
|---|---|---|---|---|---|
| Q4 class (median) | 141.6 | 141.6–141.6 | 9762 | 1 | includes our runs |
| Q8 class (median) | 95.1 | 95.1–95.1 | 9850 | 1 | includes our runs |
| Q4_K_M (our run, depth 0) | 141.6 | 3 repeats | 9762 | 3 | own measurement |
| Q8_0 (our run, depth 0) | 95.1 | 3 repeats | 9850 | 3 | own measurement |
Generation = tg128 (128 generated tokens, short context). Public rows are medians of community llama.cpp results (sources); our own runs use llama-bench b11658 on a rented GPU.
Speed vs context depth measured
Our own llama-bench runs on GeForce RTX 4090 (flash attention on, 3 repeats): generation and prompt speed with the given number of tokens already in the context.
| Quant | Context depth | Generation tok/s | vs depth 0 | Prompt tok/s |
|---|---|---|---|---|
| Q4_K_M | 0 | 141.6 | 100% | 9762 |
| Q4_K_M | 4k | 138.8 | 98% | 10050 |
| Q4_K_M | 16k | 130.8 | 92% | 9525 |
| Q4_K_M | 32k | 122 | 86% | 7956 |
| Q4_K_M | 64k | 106.5 | 75% | 6347 |
| Q4_K_M | 128k | 85 | 60% | 4522 |
| Q8_0 | 0 | 95.1 | 100% | 9850 |
| Q8_0 | 4k | 93.8 | 99% | 10238 |
| Q8_0 | 16k | 90 | 95% | 8887 |
Alternatives
Less memory that still fits Qwen3.5 9B
Smaller memory usually means a cheaper card or Mac (we do not list prices).
- 8GB VRAM class (RTX 4060 8GB, 32GB RAM): Q4_K_M, 7 GB usable, ~46 tok/s measured
- Mac mini / iMac M4 16GB: Q4_K_M, 11 GB usable, ~14 tok/s scaled from measured
- RTX 5070 12GB: Q8_0, 11 GB usable, ~68 tok/s measured
Faster for Qwen3.5 9B
- RTX 5090 32GB: Q8_0, 31 GB usable, ~156 tok/s measured
- RTX PRO 6000 96GB: Q8_0, 95 GB usable, ~153 tok/s measured
Other models on RTX 4090 24GB, similar size
- Ornith 1.5 9B (hardware page): Q8_0, fits fully, ~95 tok/s (scaled from measured)
- Qwen3-VL 8B: Q8_0, fits fully, ~102 tok/s (measured)
- Gemma 4 E4B (hardware page): Q8_0, fits fully, ~96 tok/s (scaled from measured)
- Gemma 4 12B: Q8_0, fits fully, ~64 tok/s (measured)
Memory and context limits
Q8_0 weights are 9.5 GB; the 16k f16 KV cache adds 0.59 GB. Largest context that fits in 23.0 GB usable:
| KV cache type | Max context |
|---|---|
| f16 | 256k |
| q8_0 | 512k |
| q4_0 | 1M |
Native limit 256k, 1.01M with YaRN. Full KV cache table for Qwen3.5 9B.
Copy-paste commands
The advisor's pick for this hardware: Q8_0, 16k context.
llama-server -hf unsloth/Qwen3.5-9B-GGUF:Q8_0 -c 16384 -fa on --jinja -ngl 99
OLLAMA_CONTEXT_LENGTH=16384 ollama serve ollama run hf.co/unsloth/Qwen3.5-9B-GGUF:Q8_0
FAQ
How fast is Qwen3.5 9B on RTX 4090 24GB?
About 95.1 tokens/s for generation (Q8_0 on llama.cpp CUDA, 128-token generation), 9850 tokens/s for prompt processing. Speed drops as the context fills; see the depth table.
How much memory does Qwen3.5 9B need on RTX 4090 24GB?
The advisor's pick, Q8_0, is 9.5 GB of weights plus 0.59 GB of KV cache at 16k context (10.1 GB), against 23.0 GB usable.
Is the Qwen3.5 9B speed on RTX 4090 24GB measured or estimated?
Measured: our own llama-bench run on a rented GeForce RTX 4090, including runs with 4k to 128k tokens already in context.
What can I use instead of RTX 4090 24GB for Qwen3.5 9B?
With less memory, 8GB VRAM class (RTX 4060 8GB, 32GB RAM) (~46 tok/s), Mac mini / iMac M4 16GB (~14 tok/s), RTX 5070 12GB (~68 tok/s) also fit it fully. Faster: RTX 5090 32GB (~156 tok/s), RTX PRO 6000 96GB (~153 tok/s).
What is the maximum context for Qwen3.5 9B on RTX 4090 24GB?
With an f16 KV cache about 256k tokens, 512k with q8_0 and 1M with q4_0, bounded by the model's own limit.
Related
All models on RTX 4090 24GB · Qwen3.5 9B on all hardware · VRAM tier · all measured pages · leaderboard
Compare: RTX 3090 24GB vs RTX 4090 24GB · RTX 4090 24GB vs RTX 5090 32GB · RTX 4090 24GB vs AMD RX 7900 XTX 24GB · RTX 5080 16GB vs RTX 4090 24GB