MTPLX is an MLX-native runtime for native Multi-Token-Prediction speculative decoding on Apple Silicon. Up to 2.24× faster decode at real coding temperatures (temp=0.6 / top_p=0.95 / top_k=20) using the model's own built-in MTP heads — no external drafter, no greedy hack.

bash

brew install youssofal/mtplx/mtplx
mtplx start

Project: github.com/youssofal/MTPLX

Other MTPLX checkpoints:

Qwen3.5-4B-MTPLX-Optimized-Speed — small 4-bit speed-test
Qwen3.5-4B-Optimized-MTPLX — small 8-bit

This is the speed checkpoint for MTPLX v0.1.0-preview. It combines the and embeds mtplx_runtime.json so MTPLX can run it as the optimized speed variant.

Target repository: Youssofal/Qwen3.6-27B-MTPLX-Optimized-Speed

Runtime

bash

mtplx pull Youssofal/Qwen3.6-27B-MTPLX-Optimized-Speed
mtplx run "hello" --model Youssofal/Qwen3.6-27B-MTPLX-Optimized-Speed
mtplx serve --model Youssofal/Qwen3.6-27B-MTPLX-Optimized-Speed --port 8000 --no-stats-footer

MTPLX v0.1.0-preview supports Qwen3-Next-MTP only. This model is verified for the qwen3-next-mtp backend.

Sources And Attribution

Component	Source	Revision	License
Base model	`Qwen/Qwen3.6-27B`	`6a9e13bd6fc8f0983b9b99948120bc37f49c13e9`	Apache-2.0
MTPLX conversion and runtime contract	`youssofal/mtplx`	v0.1.0-preview.1	Apache-2.0

The trunk is the MLXCommunity flat 4-bit affine conversion of compressed-tensors checkpoint at the revision listed above.

Verification

mtplx_runtime.json records:

architecture: qwen3-next-mtp
maximum MTP depth: 3
recommended profile: sustained
recommended draft-only LM head: 3-bit affine, group_size=64
recommended draft sampler: temperature 0.70, top-p 0.95, top-k 20
exactness gate: Phase 0H paged-verifier smoke
exactness max absolute diff: 0.0
verified hardware: Apple M5 Max, 128 GB unified memory
verified timestamp: 2026-05-03T23:07:00+0100

Target sampler used for the recorded contract: temperature 0.6, top-p 0.95, top-k 20, with thinking mode disabled. The draft proposal sampler is intentionally slightly hotter at temperature 0.70; target verification and residual correction remain exact.

Performance Honesty

This is the default speed lane. On the local Apple M5 Max fanmax sustained benchmark, this artifact reached 63.056 tok/s and 62.886 tok/s at depth 3 on the long-code 192-token prompt when using its contract-recommended 3-bit draft-only LM head plus draft sampler temperature 0.70, with thinking mode disabled and foreground app load reduced. The proposal change reduced the measured correction tokens from 6 to 3 and verify calls from 50 to 49 on the recorded prompt; target sampling remains temperature 0.6 / top-p 0.95 / top-k 20. A full greedy diagnostic on the same cleaned fanmax window measured 60.108 tok/s. Earlier contract evidence measured 61.527 and 60.900 tok/s, the earlier 3-bit draft-head contract measured 60.038 and 60.061 tok/s, and the older 4-bit draft-only LM head measured 57.668 tok/s on the same lane.

Files

model-*.safetensors: MLXCommunity flat 4-bit trunk shards.
mtp/weights.safetensors: calibrated prequantized INT4 MTP sidecar, nested so generic MLX vision loaders only glob the base model shards.
mtplx_runtime.json: MTPLX verified runtime contract.
MTPLX_PUBLISH_MANIFEST.json: local staging manifest with source paths, materialization method, sizes, and optional hashes.

Youssofal/Qwen3.6-27B-MTPLX-Optimized-Speed

Qwen3.6-27B MTPLX Optimized Speed

Run this with MTPLX

Runtime

Sources And Attribution

Verification

Performance Honesty

Files

Links

Youssofal/
Qwen3.6-27B-MTPLX-Optimized-Speed