The fastest way to run Qwen 3.8 on a Mac.

MTPLX is a native Mac app and a command line that runs local language models on Apple Silicon with the model's own multi-token prediction (MTP) heads. It runs Qwen 3.8 Flash Next, the 125B mixture of experts, Qwen 3.8 27B and Prism ML's Ternary Bonsai 2 27B, plus Qwen 3.6, Qwen 3.5 and Gemma 4. The model drafts several tokens ahead of itself, one batched forward pass verifies the draft, and tokens are committed through exact rejection sampling with residual correction. The sampler works at the model's native temperature, and decode runs at around twice the speed of plain decoding: measured 1.6x on a 16 GB M4 Mac mini and 2.24x on an M5 Max.

Measured speeds

Every number below was measured on a MacBook Pro M5 Max with 128 GB, fans verified at maximum, sampled at the model's own settings. Conditions and sources for every row, with the raw logs where they exist, are at mtplx.com/benchmarks.

MTPLX uses rejection sampling with residual correction at the model's native temperature. For 2.11.3, MTPLX compared a thousand four-token samples from the fast path with a thousand from the plain path at temperature 1, top-p 0.95 and top-k 20, by token id. Those measurements matched within the plain path's own noise on both Flash Next and the 27B Quality pack. From 2.12.0, image requests also use the compiled verifier, and that sampled comparison has not yet been repeated for images. The acceptance rule follows the Leviathan and Chen rejection sampling theorem; numerical equivalence of the model's execution paths is checked separately. There is no second draft model eating your RAM, and no greedy shortcut that quietly changes what the model would have said.

How MTPLX compares with mlx-serve, oMLX, LM Studio, Ollama, llama.cpp and mlx-lm, with a version, a machine and a date on every number: mtplx.com/compare.

Get it

The Mac app is the easiest way in. Download the DMG at mtplx.com, drag it to Applications, and the app takes care of everything else: it checks your hardware, recommends a model that actually fits your memory, downloads it, sets up its own Python engine (no Homebrew needed), installs fan control, puts mtplx on your PATH, and then measures your machine to pick the fastest decoding depth.

Recommended for coding: Qwen 3.8 27B Optimized Speed is a 4-bit dynamic quant with great coding speeds and good quality. Its two siblings sit right under it in the app and CLI: Bare Speed (quickest burst chat speeds, lower quality and slower on long coding tasks) and Optimized Quality (8-bit dynamic quant, the highest fidelity of the three). Qwen 3.8 Flash Next is offered as Bare Speed from 96 GB and as Optimized Speed from 128 GB, and on a Mac with 256 GB or more Flash Next Optimized Speed is the first recommendation. Qwen 3.6 Optimized Speed V2 remains available below them.

The CLI on its own:

brew install youssofal/mtplx/mtplx
mtplx start

or python3 -m pip install mtplx if you prefer pip. All releases are listed at mtplx.com/releases.

Requirements: Apple Silicon (M1 or newer), macOS 14+. The app and CLI use one recommendation policy on M3, M4 and M5: Qwen 3.5 4B Optimized Speed below 16 GB, Ternary Bonsai 2 27B from 16 GB, Qwen 3.8 27B Optimized Speed from 32 GB, and Qwen 3.8 Flash Next Optimized Speed from 256 GB, with Flash Next Optimized Quality second. M1 and M2 keep their FP16 recommendations. Installed models and explicit selections remain available.

Ternary Bonsai 2 27B and Flash Next Optimized Quality require MTPLX 2.12.0 or later.

Qwen 3.8 Flash Next on a Mac

Qwen 3.8 Flash Next is Qwen's 125B-A6B preview of the Qwen4 architecture: a hybrid GatedDeltaNet mixture of experts with Qwen Sparse Attention and a 51B-parameter n-gram table. MTPLX 2.10.0 was the first Apple Silicon backend for the family, and it runs the model's own MTP head as an exact speculative decoder. Bare Speed is offered from 96 GB of unified memory and Optimized Speed from 128 GB. MTPLX 2.12.0 adds Optimized Quality for Macs with 256 GB or more:

• Youssofal/Qwen3.8-Flash-Next-MTPLX-Optimized-Speed: dynamic 4-bit with the sparse-attention projections at 8-bit. 115.1 GB download including the 32 GB n-gram table, about 83 GB resident.
• Youssofal/Qwen3.8-Flash-Next-MTPLX-Bare-Speed: flat 4-bit, the quickest build. 106.3 GB download, about 74 GB resident.
• Youssofal/Qwen3.8-Flash-Next-MTPLX-Optimized-Quality: 8-bit group-64 body and MTP head, BF16 structural tensors, and a 4-bit group-32 n-gram table. 169.96 GB download (169,958,537,520 bytes); the weights need about 128.5 GiB. It has not yet been run on a 256 GB Mac, and its speed has not been measured.

The n-gram table streams from SSD on every Mac, so only the weights stay in memory. Context window 262,144 tokens; 261,120-token prompts decode. Image input works. In the app, pick "Qwen 3.8 Flash-Next Optimized Speed"; from the terminal:

mtplx serve --model Youssofal/Qwen3.8-Flash-Next-MTPLX-Optimized-Speed

Then point OpenCode, Pi, Hermes, Claude Code, Cline, Cursor or anything that speaks the OpenAI or Anthropic API at http://127.0.0.1:8000. The guide with every measured number and its conditions: mtplx.com/models/qwen3.8-flash-next.

Bonsai 2 on a Mac

Youssofal/Ternary-Bonsai-2-27B-MTPLX-Optimized-Speed is a compact ternary 27B model from Prism ML with vision and MTP. It is the first recommendation on M3, M4 and M5 Macs with 16 to 31 GB. The old Bonsai-3.8-27B-MTPLX-Optimized-Speed folder and mtplx-bonsai-38-27b-optimized-speed served ID resolve to the same entry; clients use mtplx-bonsai-2-27b-optimized-speed.

The pack is 8.85 GB with its vision tower and the Qwen3.8-27B MTP head, which defaults to depth 1. Reasoning effort is medium by default; xhigh is also available. On an M5 Max it decodes 64.4 tok/s at 4K and 57.1 at 16K, against 52.6 and 51.0 for the 4-bit 27B, in about half the memory. On a 16 GB Mac it gets an 8,192-token window, with a measured peak of 11.80 GiB under a 16 GB memory budget; agent clients such as OpenCode and Hermes need 18 GB or more.

Qwen 3.8 27B on a Mac

Qwen 3.8 27B is the coding flagship for Macs with 32 GB or more. MTPLX shipped it on 15 August 2026, the day after Qwen released it. Three packs, each with an FP16 sibling for M1 and M2 that the app and CLI pick automatically:

• Youssofal/Qwen3.8-27B-MTPLX-Optimized-Speed: 4-bit dynamic, 20.4 GB, 23.6 GB peak. The default for coding. Against the bf16 model on a mixed corpus of code, prose and JSON it agrees on 96.0 percent of top-1 tokens with a KL divergence of 0.012.
• Youssofal/Qwen3.8-27B-MTPLX-Bare-Speed: flat 4-bit, 16.0 GB, 17.0 GB peak. Quickest chat speeds.
• Youssofal/Qwen3.8-27B-MTPLX-Optimized-Quality: 8-bit dynamic, 29.4 GB, 32.7 GB peak, for 36 GB or more. 99.3 percent top-1 agreement with bf16, KL 0.0005.

The guide: mtplx.com/models/qwen3.8-27b.

Models and recommended settings

The catalog lists MTPLX packs under Youssofal. For measured packs, "Fits" is the catalog peak while serving, next to the smallest Mac the app and CLI will offer it on. The preset column is what MTPLX resolves by itself, so this table is what you get by doing nothing.