Qwen3.5-9B MTPLX Optimized Speed
Fast local 9B inference for Apple Silicon, packaged for MTPLX native Multi-Token-Prediction speculative decoding.
This is the 9B speed checkpoint: a 6-bit MLX body with BF16 MTP heads, tuned as the stronger small-Mac option above the 4B release.
For coding and agent work at the same size, see MiMo V2.6 Qwen 9B Optimized Speed, Xiaomi's fine-tune of this model with the same 6-bit recipe. On M3, M4 and M5 Macs with 16 GB or more, MTPLX 2.12.0 suggests it before this pack.
Run It
brew install youssofal/mtplx/mtplx
mtplx start
mtplx run "hello" --model Youssofal/Qwen3.5-9B-MTPLX-Optimized-Speed
For an OpenAI-compatible local server:
mtplx serve --model Youssofal/Qwen3.5-9B-MTPLX-Optimized-Speed --profile sustained --max --port 8000 --no-stats-footer
Why This Exists
MTPLX uses the model's own MTP heads to generate draft tokens, then verifies those tokens with the main model. When the draft heads are well-matched, you get higher throughput without running a separate drafter model.
MTPLX reads mtplx_runtime.json and selects the measured defaults automatically.
Recommended Runtime Defaults
| Setting | Value |
|---|---|
| Backend | qwen3-next-mtp |
| Default depth | D2 |
| Target sampler | temp=0.60, top_p=0.95, top_k=20 |
| Draft sampler | temp=0.60, top_p=0.95, top_k=20 |
| Profile | sustained |
| Benchmark fan mode | max |
Performance
Measured in MTPLX on Apple Silicon using the release runtime path.
| Mode | TPS | Verify time | Acceptance |
|---|---|---|---|
| AR baseline | 64.96 | - | - |
| D1 comparison | 92.87 | 6.83s | 0.9120 |
| D2 promoted default | 101.32 | 4.13s | 0.9398, 0.8102 |
| D3 comparison | 96.30 | 4.58s | 0.9278, 0.7732, 0.6443 |
Model Build
| Component | Format |
|---|---|
| Main body | 6-bit MLX affine, group size 64 |
| MTP heads | BF16 native MTP sidecar |
| Sampler | target and draft temp=0.60, top_p=0.95, top_k=20 |
This is not a full-precision checkpoint. It is built for fast local use on Apple Silicon through MTPLX.
Files
model-*.safetensors: MLX body shardsmtp.safetensors: MTP sidecarmtplx_runtime.json: MTPLX runtime contract and measured defaultsMTPLX_PUBLISH_MANIFEST.json: file sizes and artifact metadata- tokenizer and config files for local loading