DeepSeek-V4.1-Flash-REAP50-MLX-mixed-4_8bit
MLX (Apple Silicon) build of DeepSeek-V4.1-Flash — 754.6B parameters: 40 layers x 384 routed experts, MLA with cross-layer KV-cache sharing (4 compressor-owning layers serve all 40), a two-layer engram hashed n-gram embedding whose tables alone are 196.6B parameters (~40% of the checkpoint), staggered Sinkhorn hyper-connections, and per-layer attention sinks — quantized to 4-bit experts / 8-bit attention&shared / 8-bit engram.
These files are modified: dequantized from the FP8/FP4 release (bit-exact decode of the 32x32-block ue8m0 fp8 and per-32 fp4 packing) and re-quantized; the architecture is unchanged. The 3 multi-token-prediction layers (DSpark markov/confidence heads) are not included; the vision tower and aligner are carried unmodified but the runtime is text-only.
Runtime
deepseek_v41 exists in no runtime — not transformers, not mlx-lm, not mlx-vlm. This
checkpoint loads only through the port:
git clone https://github.com/PipeNetwork/deepseek-v41-mlx && cd deepseek-v41-mlx && pip install -r requirements.txt
python scripts/smoke_generate.py /path/to/DeepSeek-V4.1-Flash-REAP50-MLX-mixed-4_8bit
from deepseek_v41_mlx.load import load
model, tokenizer = load("/path/to/DeepSeek-V4.1-Flash-REAP50-MLX-mixed-4_8bit")
The port was validated against DeepSeek's own inference/model.py (the only reference): fp32
tiny-config parity 1e-6 across prefill / cached decode / chunked prefill, the three QAT
fake-quant ops bit-exact, and negative controls proving the fragile paths are load-bearing
(rope-inverse 0.84, attention sinks 0.65, cross-layer sharing 0.56 logit shift when broken).
Strict loading reports zero missing / zero unexpected tensors. One reference decode bug was
found and documented (odd-step indexer reads the wrong layer's keys; 0.67 logit shift — the port
uses the owner's cache): see docs/upstream-notes.md in the repo.
Size and what is quantized
274.7 GB on disk. RAM: 320 GB-class (275 GB resident).
| group | share of parameters | this build |
|---|---|---|
routed experts (40 x 384, w1/w2/w3) | 543.6B (72%) | 4-bit, group 64 |
| engram tables (2 x [384,006,168 x 256]) | 196.6B (26%) | 8-bit, group 64 |
attention (MLA), shared experts, embeddings, head | ~14B | 8-bit, group 64 |
wo_a (block-diagonal output LoRA), hyper-connections, sinks, router biases, compressor, indexer keys, norms | — | unquantized (bf16/fp32) |
REAP pruning
This build keeps 192 of 384 routed experts per layer (50% pruned; all 40 layers are routed MoE in V4.1 — no hash layers — so all are pruned; attention, shared experts, engram tables and the router structure are untouched), ranked by REAP saliency: mean applied routing weight x ‖expert output‖ over 65,536 calibration tokens (wikitext-2 train, ten languages of Wikipedia, code; zero 32-gram overlap with the eval set), collected by running the full quantized build. Kept experts carry 72.7% of saliency mass on average; two disjoint halves of the calibration set choose the same kept set 88.4% of the time. Pruning was applied to the already-quantized build (expert subsetting and affine quantization act on different axes — exactly equivalent to pruning bf16 and requantizing). Saliency retention is not a quality measure; the perplexity below is.
Quality
Per-layer divergence ladder vs the bf16-dequantized reference — every one of the 40 decoder layers run on identical inputs (16,384 tokens of wikitext-2), teacher-forced and free-running, with the ladder's arithmetic asserted bit-identical to this converter's:
| recipe | teacher-forced (mean) | free-running (final layer) | cosine (final) |
|---|---|---|---|
| 8bit | 0.0084 | 0.1243 | 0.9910 |
| 6bit | 0.0177 | 0.1393 | 0.9886 |
| 4bit-engram4 | 0.0579 | 0.2714 | 0.9634 |
| mixed 4/8, engram as shipped (fp8/ue8m0) | 0.0335 | 0.1948 | 0.9800 |
| mixed 4/8, engram 6-bit (this set's 1 TB build) | 0.0335 | 0.1945 | 0.9801 |
| mixed 4/8, engram 4-bit (this set's 512 GB build) | 0.0342 | 0.2090 | 0.9775 |
The engram finding that shapes this set: 6-bit engram is indistinguishable from the shipped fp8 tables (free-running 0.1945 vs 0.1948) while 4-bit engram costs +7.3% free-running — but the engram-6 build is 477 GB and a 512 GiB machine cannot run it, so the engram-4 build is the one that fits and the engram-6 build serves 1 TB machines.
Perplexity (wikitext-2 test, 286,580 tokens in 140 windows of 2048, through this runtime): 3.3833 [3.1696, 3.6153]. Greedy generation is coherent (collapse check). Paired against the unpruned build on identical windows: ratio x1.1681 [1.1407, 1.1991], worse on 138/140 windows.
License
MIT, as the upstream model. Port code: https://github.com/PipeNetwork/deepseek-v41-mlx.