About this conversion
This repository contains an oQ4 mixed-precision MLX conversion produced directly from Qwen's BF16 weights. Layer sensitivity was measured with a validated local proxy. Every final tensor, including the native MTP head, was rebuilt from the official BF16 checkpoint. Group size 32 supports the model's 160-wide hashed n-gram embedding tables.
| Item | Value |
|---|---|
| Repository | Vontra/Qwen3.8-Flash-Next-MLX-oQ4-MTP |
| Base model | Qwen/Qwen3.8-Flash-Next |
| Format | MLX safetensors |
| Quantisation | oQ4 mixed precision, 4-bit affine base with protected modules at 5/8-bit |
| Base group size | 32 |
| Protected modules | 232 |
| Native MTP | Included, one Qwen4Exp draft block |
| Weight tensors | 3,747 total, including 76 converted MTP tensors |
| Weight shards | 22 |
| Weight size | 113.33 GB, 105.54 GiB |
| Configured context | 262,144 tokens |
| Architecture | qwen4_exp vision-language sparse MoE |
The upstream tokenizer, chat template, vision processor, generation configuration, and native MTP configuration are preserved.
[!IMPORTANT] This checkpoint requires an oMLX or MLX-VLM runtime with explicit
qwen4_expnative-MTP support. Stock runtimes that do not construct the Qwen4Exp MTP module may reject the 76 MTP tensors during strict weight loading.
[!CAUTION] Do not attach a Qwen3.8 27B drafter to this model. Flash Next has different hidden dimensions and ships its own matching MTP block here.
Download and use
hf download Vontra/Qwen3.8-Flash-Next-MLX-oQ4-MTP \
--local-dir Qwen3.8-Flash-Next-MLX-oQ4-MTP
Add the downloaded directory to an MTP-capable oMLX installation, select the model, and enable native MTP in its model settings.
Apple M3 Studio performance
Validated with native MTP enabled in oMLX on an Apple M3 Studio:
| Test | Output tokens | Speed |
|---|---|---|
| Raw completion, first measured run | 32 | 29.4 tokens/s |
| Raw completion, warmed | 32 | 34.4 tokens/s |
| Exact-instruction chat | 27 | 17.4 tokens/s |
| Casual chat | 71 | 39.7 tokens/s |
The two deterministic raw-completion runs produced identical output. The exact-instruction test returned hello, and the longer chat completed coherently without repetition or cache-reconciliation errors. Native MTP remained active throughout, with 58.3 to 89.5% draft acceptance across these tests.
Results vary with prompt length, cache state, sampling settings, runtime version, and memory pressure.
Architecture
Qwen3.8 Flash Next combines Gated DeltaNet, Qwen Sparse Attention, sparse mixture-of-experts layers, widened gated residual streams, hashed bigram and trigram embeddings, and a native next-token prediction block for speculative decoding.
| Architecture detail | Upstream value |
|---|---|
| Language-model parameters | 125B total / 6B active |
| N-gram embedding | 51B parameters |
| Layers | 48 |
| Routed / active experts | 512 / 10, plus 1 shared |
| Attention heads / KV heads | 24 / 2 |
| Hidden size | 2,560 |
| Native configured context | 262,144 tokens |
| Native MTP draft blocks | 1 |
For upstream evaluations, intended use, limitations, safety guidance, and the complete architecture discussion, see the original model card.
Conversion and validation
- The converter read the official BF16 checkpoint directly.
- Sensitivity-guided allocation used a 4-bit base and 232 protected or overridden modules.
- Structural validation checked all 3,747 indexed tensors and all 22 shards.
- MTP validation confirmed one configured draft layer and 76 converted MTP tensor entries.
- Live generation validation covered deterministic completion, exact-instruction chat, coherent chat, MTP telemetry, and cache rollback.
This is a community conversion, not an official Qwen release.
License and attribution
The upstream model is released under the Qwen Community License 1.0. The required licence text is included in this repository.
Model design, training, evaluations, and upstream documentation belong to Qwen and the original contributors. The MLX conversion and packaging are provided by Vontra.
Choose for your Mac
64GB Macs · 128GB Macs · 256GB Macs
No measured memory tier is assigned here. The collections use published M3 Studio peaks with at least 25% nominal headroom; fit on other Macs is an estimate, and full context is not guaranteed. Start with short context and one request.
Runtime and evidence
The exact tested oMLX application version is not recorded here; a library version is not an app version. The original performance tables retain their benchmark conditions and speed figures; this documentation update adds no new test results.
An unresolved long-generation repetition report involves oQ4-MTP; this update does not establish a fix.
Quick start and demo prompt
hf download Vontra/Qwen3.8-Flash-Next-MLX-oQ4-MTP --local-dir ./models/Qwen3.8-Flash-Next-MLX-oQ4-MTP
Add the downloaded folder to oMLX model directories, refresh the list, and follow this card's architecture and MTP compatibility requirements before loading.
Try this in a new chat with a 128-token output limit:
Explain why the sky looks blue in three short sentences.
This is a demo prompt to try, not a recorded successful run; a captured demonstration for this documentation update is not yet available.