284B-parameter MoE (21B active) in 101 GiB — built to fit and run on 128 GB Apple Silicon. Config-I mixed-precision quantization at 3.05 bpw effective, standard MLX format.

Config-I quantization of deepseek-ai/DeepSeek-V4-Flash-0731 — the official 2026-07-31 release, superseding the preview — (43 layers, 256 routed experts top-6, hash routing on the first 3 layers, MLA attention, mHC hyper-connections, DSA indexer). The policy applies aggressive 2-bit compression to expert MLPs (where MoE is most tolerant), protects attention at 4-bit, and shields boundary layers, routing, and embeddings at higher precision. See the Config-I policy writeup for the derivation.

Compression

	Size
FP8/FP4 source	167 GB
BF16 equivalent	~570 GB
Config-I (3.05 bpw)	108 GB (101 GiB)

Policy

Tensor group	Precision
Expert gate/up (routed + shared)	2-bit
Expert down	3-bit
MLA attention + indexer + compressor	4-bit
Boundary layers (first 2 + last 2): attention	8-bit
Boundary layers: experts	4-bit
Embeddings + head	8-bit
Router gates, norms, mHC params	f16

Group size 64 throughout. The boundary-expert 4-bit choice (vs 8-bit in earlier Config-I releases) is what brings the artifact under the 128 GB unified-memory ceiling with headroom for KV cache and activations.

Status and testing

Note: this MLX build has had lighter testing than the GGUF sibling. If you want the more thoroughly measured artifact (perplexity, backend traps, behavioral notes), start there.

📖 How to run it well: the offlabel operating guide covers sampling, failure modes, and the fixes (GGUF-focused, but the sampling and model-behavior notes carry over).

Verified: loads and generates coherently via python mlx-lm (greedy smoke: correctly completes "The opening line of Moby Dick is" and continues cleanly). The model class and quant config load without changes.
MLX-specific quality numbers are pending. This artifact is a distinct quantization from the GGUF sibling (3.05 bpw affine here vs 2.88 bpw TQ hybrid there), so the sibling's perplexity does not transfer and is not quoted here. A full MLX-side PPL / MMLU / NIAH pass is queued; numbers land here when done.
Sibling GGUF (for CUDA / DGX Spark / non-MLX): DeepSeek-V4-Flash-ConfigI-GGUF, which carries measured perplexity, backend notes, and observed behaviors. Note: the fast DSv4 engine on Apple Silicon (DwarfStar / antirez ds4, ~5x decode) runs the GGUF/ds4 format, not MLX; if raw speed matters more than the MLX toolchain, use that path.

Using it (sampling that matters)

Sampling floor: DeepSeek's official settings are temperature 1.0, top_p 0.95 (top_p 1.0 outside agentic use). Greedy decoding has a documented looping tendency on this model family; do not evaluate or run it greedy.
Give it a real output budget. Reasoning is verbose by design (the vendor allows very long outputs at higher reasoning effort); a small max_tokens truncates mid-thought and looks like a failure.
Observed on the sibling quant (may transfer, unverified on this one): long unattended symbolic-math derivations can fall into repetition; anti-repetition sampling fixes it there. Route hard math with supervision until MLX-side confirmation.

Running it

mlx-swift-lm: deepseek_v4 is a registered model type — loads directly.
python mlx-lm: requires the deepseek_v4 model class (upstream PR pending). Until it lands, drop the included deepseek_v4.py into mlx_lm/models/.

Peak memory during generation: ~109 GB. On a 128 GB Mac, close other memory-heavy apps; raising iogpu.wired_limit_mb helps sustained throughput.

License

Inherits the DeepSeek model license from the base model. Quantization by thetom-ai.

thetom-ai/DeepSeek-V4-Flash-ConfigI-MLX

DeepSeek-V4-Flash — Config-I (MLX)