--- license: apache-2.0 license_link: https://huggingface.co/Qwen/Qwen3.5-4B/blob/main/LICENSE thumbnail: https://huggingface.co/AlexAtomic/qwen35-4b-GGUF/resolve/main/hero.png base_model: - Qwen/Qwen3.5-4B base_model_relation: quantized quantized_by: AlexAtomic pipeline_tag: text-generation library_name: gguf tags: - atomic-chat - qwen - qwen3 - gguf - imatrix - quantized - llama.cpp ---
Scores are Qwen's published results for the base `Qwen/Qwen3.5-4B`. Quantization preserves the large majority of this; `Q4_K_M` and up sit within a point or two of full precision.
## Choosing a quant
| Quant | Size | Notes |
|---|---|---|
| `Q2_K` | 1.9 GB | Smallest. Minimal RAM, clear quality drop. |
| `IQ3_M` | 2.2 GB | Beats Q3 at similar size thanks to imatrix. Best low-RAM pick. |
| `Q3_K_M` | 2.3 GB | Low quality but usable. |
| `Q3_K_L` | 2.4 GB | A step above Q3_K_M. |
| `IQ4_XS` | 2.5 GB | Excellent quality for size. Recommended low-bit. |
| `Q4_K_S` | 2.6 GB | Compact Q4, fast. |
| **`Q4_K_M`** | 2.7 GB | **Recommended default. Best balance of size, speed and quality.** |
| **`UD-Q4_K_XL`** | 2.9 GB | **Dynamic. Embeddings and output kept at Q8_0 for higher quality at a Q4 footprint.** |
| `Q5_K_S` | 3.0 GB | Higher quality. |
| `Q5_K_M` | 3.1 GB | Higher quality, low loss. |
| `Q6_K` | 3.5 GB | Near lossless. |
| `Q8_0` | 4.5 GB | Effectively lossless, reference quality. |
> [!TIP]
> Pick the largest file that fits your (V)RAM with room for context. `Q4_K_M` or `UD-Q4_K_XL` is the sweet spot for most setups; `Q6_K` or `Q8_0` for maximum fidelity.
## Get started
Run Qwen3.5 4B locally with:
- **[Atomic Chat](https://atomic.chat):** the easiest path. Open the app, search `AlexAtomic/qwen35-4b-GGUF`, pick a quant, hit **Use this model**.
- **llama.cpp:** `llama-server -hf AlexAtomic/qwen35-4b-GGUF:Q4_K_M --jinja -c 8192`
- **Ollama:** `ollama run hf.co/AlexAtomic/qwen35-4b-GGUF:Q4_K_M`
- **LM Studio / Jan:** search the repo id, download any quant.
## Best practices
| Parameter | Value |
|---|---|
| temperature | 0.7 |
| top_p | 0.8 |
| top_k | 20 |
| min_p | 0.0 |
| presence_penalty | 1.5 |
| repetition_penalty | 1.0 |
Qwen's recommended Instruct (non-thinking) settings. Thinking mode for general tasks: temperature=1.0, top_p=0.95, top_k=20, min_p=0.0, presence_penalty=1.5, repetition_penalty=1.0.
## Run in llama.cpp
```bash
git clone https://github.com/ggerganov/llama.cpp
cmake llama.cpp -B llama.cpp/build -DBUILD_SHARED_LIBS=OFF -DGGML_CUDA=ON
cmake --build llama.cpp/build --config Release -j --target llama-cli llama-server
```
```bash
./llama.cpp/build/bin/llama-server \
-hf AlexAtomic/qwen35-4b-GGUF:UD-Q4_K_XL \
--jinja -ngl 99 -c 8192 -fa on
```
## How these were made
1. Download `Qwen/Qwen3.5-4B` (original weights).
2. Convert to f16 GGUF with [llama.cpp](https://github.com/ggerganov/llama.cpp).
3. Build an importance matrix over `calibration_datav3` (100 chunks).
4. Quantize the full ladder with `--imatrix`.
5. `UD-Q4_K_XL` additionally pins the token-embedding and output tensors to `Q8_0`.
## License
Released by Qwen under the Apache 2.0 license. Quantized by Atomic Chat.