What changed
- Every routed-expert
w1, w3, and w2 matrix uses symmetric W2A16
quantization with group size 128.
- Packed weights use the compressed-tensors 0.17.0 WNA16 format with FP16 group
scales and INT32 packed values.
- Non-routed tensors retain their source values and dtypes, including the native
DeepSeek FP8 attention and shared-expert weights.
- The MTP/DSpark draft layers are omitted.
num_nextn_predict_layers is zero.
- The resulting checkpoint contains 45 safetensors shards. The three omitted
source shards contained only MTP tensors.
How it was created
The conversion used the official checkpoint at revision
7872f01b1d1fe23eabc4c98b48bffcef5a386062.
It processed one source shard at a time and wrote checksum-bound, resumable
safetensors shards.
For each routed-expert matrix, the converter:
- used Intel AutoRound's DeepSeek V4 path to decode the source MXFP4/E8M0
representation;
- fitted symmetric 2-bit weights with group size 128;
- weighted the scale search with Antirez's routed-expert activation imatrix;
- packed the signed codes with compressed-tensors 0.17.0; and
- recorded weighted and unweighted reconstruction error in
conversion-metrics.json.
The conversion selected imatrix-weighted RTN after a bounded comparison on 24
matrices from layers 0, 26, 37, and 42. It improved weighted reconstruction
error in all 24 comparisons. The median improvement was 31.03% relative to
plain RTN. This result measures reconstruction error, not end-to-end model
quality.
The Antirez imatrix predates the 0731 checkpoint. Antirez later reused it for
0731 GGUFs, and the 24-matrix comparison showed that it improved this WNA16
conversion, but it is not a 0731-native calibration run.
Table with columns: Component, Revision or version| Component | Revision or version |
|---|
| Base checkpoint | deepseek-ai/DeepSeek-V4-Flash-0731@7872f01b1d1fe23eabc4c98b48bffcef5a386062 |
| Routed-expert imatrix | antirez/deepseek-v4-gguf@e7f04037032990db0346398d249baf9fb9df1ccc |
| Imatrix content SHA-256 | 02a7c78c29875e4653d6ce21d8821c02161e83ed90c506bdd8d275f76d4ac97e |
| AutoRound | intel/auto-round@f17d9cd4b36982006bad21ff87127aac739072e3 |
| compressed-tensors | 0.17.0 |
| Humming |
The full conversion ran on one A100 80 GB VM and used 112.9 GiB peak host
memory with no swap.
The immutable weight snapshot is
75d9286c37f3037f3ab390cfbc10747466eac714.
It contains 54 files totaling 82,464,249,582 bytes, including 45 model shards.
Runtime compatibility
This checkpoint requires the experimental code in
Whamp/vllm#1, based on
haosdent/vllm@12810046c799cbe874967e19b1c0fa134ab7b209.
Club-3090 keeps a checksum-pinned deployment copy of the patches at
Whamp/club-3090@357661d6.
The final tested vLLM tree was
aeb62948e33074514a742d19c2f9a1a3c2ee3e1f.
The patches provide:
- compressed-tensors W2 Humming MoE loading;
- separate routed-expert and native DeepSeek FP8 handling;
- DeepSeek V4 execution on SM86; and
- RTX 3090 sparse-attention fallbacks for kernels that exceed SM86 shared
memory.
Stock vLLM does not implement this complete path. Do not expect
vllm serve hampsonw/DeepSeek-V4-Flash-0731-WNA16 to work in an unpatched
environment.
Historical runtime result
The final runtime test used four RTX 3090 GPUs with tensor parallelism 4. It:
- loaded all 45 shards;
- served a 215,000-token maximum context with
max_num_seqs=4;
- measured about 60.8 single-stream decode tokens/s;
- measured about 969 prefill tokens/s;
- retrieved the correct value from a 204,900-token prompt; and
- passed short-request concurrency checks with two and four requests.
Only about 141–142 MiB remained free on each GPU. These results show that the
runtime path works. They do not establish model quality.
Quality result
DeepSWE ran the same coding task twice: first with concurrent serving, then with
one worker and no other requests. Both runs failed the same way. The model kept
rereading files, never edited or tested the code, and produced no patch. The
second run rules out concurrency as the cause.
Other DeepSeek V4 versions completed the task:
- IQ2_XXS produced a 22.5 KB patch, passed 78 of 80 feature tests, and preserved
all 116 existing tests.
- Three FP8 runs produced 35–51 KB patches and passed 90–92.5% of the feature
tests.
This quant is withdrawn. The vLLM runtime remains useful for testing future
quants.
Other limits remain:
- MTP/DSpark is absent.
- The artifact uses one uniform W2 recipe for every routed projection.
- The calibration imatrix came from the pre-0731 model.
- Runtime support depends on research patches and JIT-compiled Humming kernels.
Reproduction
The converter, pilot, resumable writer, upload verifier, runtime patches, and
research record live in the
feat/deepseek-v4-lowbit-vllm
branch of club-3090. Start with:
Credits
- DeepSeek created and released DeepSeek-V4-Flash-0731.
- Antirez created the routed-expert imatrix used to guide this quantization.
- Intel AutoRound provided the source dequantization and RTN scale-search
primitives.
- Neural Magic and the vLLM project provide the compressed-tensors format and
loader infrastructure.
- InclusionAI provides the Humming WNA16 kernels.
- Haosdent and Lasimeri developed the Ampere DeepSeek V4 work that made the
runtime experiment possible.
License
The base checkpoint and this redistributed quantization use the
MIT License.
DeepSeek's copyright and permission notice are included in this repository.