mlx-community/Qwen3.6-35B-A3B-OptiQ-4bit-REAP-19B

Built with mlx-optiq, the MLX-native toolkit to quantize, prune, fine-tune, and serve LLMs locally on Apple Silicon. All OptiQ models · Docs

13.8 GB instead of 23.0 GB. 11.6 GB of memory to run instead of 24.5 GB. Capability Score 76.57 against the parent's 80.03.

	Parent	This model
On disk	23.0 GB	13.8 GB	−40%
Peak memory	24.5 GB	11.6 GB	−53%
Parameters	35.1B	18.8B	−47%
Decode	47.0	54.7
Capability Score	80.03	76.57	-3.47

50% of the routed experts are removed from mlx-community/Qwen3.6-35B-A3B-OptiQ-4bit; active parameters per token are unchanged, since top-8 routing is preserved and only the stored expert bank shrinks. That is why it gets smaller without getting slower.

Retained experts are copied bit-for-bit from the parent quant. Nothing is dequantized, re-quantized, merged, or retrained.

What pruning costs

Benchmark	Parent	This model	Δ
MMLU	83.7	62.3	-21.4
GSM8K	87.9	90.5	+2.6
IFEval	72.6	76.9	+4.3
BFCL-V3	92.5	91.5	-1.0
HumanEval	91.5	90.2	-1.3
HashHop	52.0	48.0	-4.0
Capability Score	80.03	76.57	-3.47

Details

Property	Value
Experts retained	128 of 256 per layer
Active experts per token	8 (unchanged)
Allocation	uniform (128 of 256 in every layer)
Size	13.8 GB (parent 23.0 GB)
Parameters	18.8B (parent 35.1B)
Selection	REAP — mean of router weight × expert output norm, over the tokens each expert served
Calibration	optiq six-domain mix, 8 samples
MTP sidecar	preserved

Use it

pip install mlx-optiq
optiq serve --model mlx-community/Qwen3.6-35B-A3B-OptiQ-4bit-REAP-19B

from mlx_lm import load, generate
model, tok = load("mlx-community/Qwen3.6-35B-A3B-OptiQ-4bit-REAP-19B")
print(generate(model, tok, prompt="Hello", max_tokens=64))

Method

Expert pruning follows REAP (Cerebras Research, ICLR 2026 — REAP the Experts: Why Pruning Prevails for One-Shot MoE Compression). Experts are ranked by the conditional mean of router weight × expert output norm over calibration data; the lowest-ranked are removed and the router is sliced to match.

OptiQ applies it in the quantized domain — directly on a quantized checkpoint, with no BF16 parent and no dequantization of survivors — via optiq prune-experts. See the pruning docs.