Qwen3.8-Flash-Next-MLX-4bit

Qwen3.8-Flash-Next MLX 4-bit

Local MLX conversion of Qwen/Qwen3.8-Flash-Next.

• Language weights: affine 4-bit, group size 64.
• PLE n-gram embedding: affine 4-bit, group size 32.
• MoE routing gates: affine 8-bit, group size 64.
• Vision tower: BF16.
• Native MTP tensors are not included in this base checkpoint.

This model requires the Qwen4-Exp support in the accompanying local mlx-vlm checkout.

Runtime setup

Qwen4-Exp is newer than the current stock mlx-vlm model registry. Until the implementation is upstreamed, use the runtime module bundled in this repo:

git clone https://github.com/Blaizzy/mlx-vlm.git
cp -R mlx_vlm_qwen4_exp/qwen4_exp mlx-vlm/mlx_vlm/models/qwen4_exp

python3 -m venv .venv
.venv/bin/pip install -e ./mlx-vlm
.venv/bin/pip install --upgrade git+https://github.com/huggingface/transformers.git

.venv/bin/mlx_vlm.generate \
  --model . \
  --prompt "Hello!" \
  --max-tokens 256

The bundled module registers the Qwen3-VL-compatible processor and multimodal chat format automatically. Native MTP speculative decoding is not included.

For an interactive terminal chat after setup:

.venv/bin/mlx_vlm.chat \
  --model . \
  --max-tokens 512 \
  --temperature 0.0

Commands inside the chat include /image <path>, /clear, and /exit.

LM Studio (experimental)

LM Studio's current MLX runtime does not yet bundle qwen4_exp. From this model directory, install the included compatibility module:

chmod +x install_lmstudio_patch.sh
./install_lmstudio_patch.sh

Then unload and reload the model in LM Studio. On a 128 GB Mac, LM Studio may still reject the checkpoint based on its conservative memory estimate. Enable Developer Mode and select Settings → Hardware → Model loading guardrails → OFF only after closing other memory-heavy applications. The measured peak is about 104.1 GB, so smaller-memory Macs are not recommended.

Verified with LM Studio 0.4.21 (Build 2), MLX runtime 1.11.0, including multi-turn text chat and image understanding. The compatibility module also supplies the sparse-attention path needed by larger image prompts. Updating LM Studio's MLX runtime may replace the installed module; rerun the script if qwen4_exp becomes unrecognized again or vision generation fails after an update.

Verified locally

Tested on a 128 GB Apple M5 Max:

• Text: 9.13 prompt tokens/s, 60.95 generation tokens/s.
• Image + text: 214.84 prompt tokens/s, 48.92 generation tokens/s.
• Peak unified memory: 104.07 GB.
• LM Studio multi-turn text chat: 36.63 generation tokens/s.
• LM Studio image understanding: 31.01 generation tokens/s.