Ampere (RTX 3090, sm86) has no native FP8 or MXFP4 tensor cores. The released 0731 checkpoint (FP8+MXFP4) using mainline vLLM has no officially supported loading path.

Using AppMana's vLLM fork at its current public tip plus the two patches shipped in this repository's serving/ folder, this quant enables serving on Ampere.

Tested on 8x RTX 3090 (24GB, sm86). See "What to expect" below.

What this is

DeepSeek-V4-Flash-0731 converted to a format that runs on Ampere GPUs:

Experts: MXFP4 (E2M1) — lossless. On sm86, E2M1 is reinterpreted as signed INT4 and run through Ampere INT4 tensor cores via Marlin. E8M0 power-of-2 scales applied in epilogue. No quality loss vs original.
Dense linears: FP8 E4M3 → INT8 (channelwise). Lossy but minimal: measured 40 dB signal-to-noise ratio (~1% mean relative error) on the original checkpoint's FP8 weights after round-trip. For comparison, a typical W4A16 quant measures ~20-30 dB.
KV cache: int8_ds_mla. Doubles context vs fp8 (437K vs ~220K on 8x24GB).
DSpark: 3 MTP draft stages preserved from 0731 source. Observed 0% draft acceptance with int8 KV on sm86. Disable for production.

How it was created

Converted with tools/ampere/dsv4_requant_checkpoint.py from the AppMana vllm-consumer-nvidia-platforms fork:

bash

python tools/ampere/dsv4_requant_checkpoint.py \
  --src deepseek-ai/DeepSeek-V4-Flash-0731 \
  --dst ./output \
  --expert-format mxfp4 \
  --dense-int8-strategy channel \
  --device cuda:0 \
  --overwrite

MXFP4 path is 95% passthrough — expert weights copied byte-for-byte, only ~8 FP8 linears per shard requanted to INT8. Conversion takes ~15-30 min on a single GPU. See serving/convert.sh. Regenerate with serving/convert.sh; compare shard hashes against serving/checksums/ (sha256 of the published files).

Source: deepseek-ai/DeepSeek-V4-Flash-0731 Fork: AppMana/forks-vllm-consumer-nvidia-platforms branch appmana/upstream-merge, tip 760ced86b + the two serving/patches (== commit 623739503) Similar quants: appmana/deepseek-v4-mxfp4-int8 (pre-0731, no DSpark), appmana/deepseek-v4-int4-int8 (0731, INT4 experts, faster but less headroom)

What to expect

Tested on 8x RTX 3090 (24GB, PCIe, no NVLink), CUDA 13.1, torch 2.13.0+cu130, fork commit 623739503 (= public tip 760ced86b + the two serving/patches). One bench harness, Sep 2026:

Profile	KV pool	Single	4-way agg	Notes
TP4xPP2, async, 512K window (recommended default)	1,008,842 tok = 1.92x @512K	49 tok/s	135 tok/s	492K-token ingest validated E2E
TP8, async, 262K	413,887 tok = 1.58x @262K	58 tok/s	139 tok/s	max single-stream
TP8, sync, 262K + 20 GiB CPU offload	461,011 tok + CPU spill	49 tok/s	120 tok/s	clean teardown

Context auto-fit: 524,288-token window with a 1.0M-token pool
Single-stream is below the pre-merge engine's 62 tok/s — the merged engine trades ~10-15% single-stream decode for 2.3x context and a fixed long-context prefill path (details in serving/profiles.md)
Correct math, coherent long-form generation, working tool calls
No quality evals yet — evaluate before production use
GMU=0.93 is the ceiling at the 512K window (0.95 always OOMs on 24GB)
--max-num-batched-tokens 128 gives 100% Triton JIT cache hit

No attempt was made to make DSpark work. We prioritized serving context.

No claims are made for suitability for any purpose.

The only intent is to provide inspiration for owners of 8x3090 rigs.

How to serve

Requires the AppMana fork plus the two patches shipped in serving/patches/, and flash-mla==2.0.0+8ec3de6.

The flash-mla wheel index is https://appmana.github.io/forks-flash-mla-int/, which redirects to GitHub releases. If it is unavailable, the sm86 attention path has no fallback. Consider mirroring the wheel if you depend on this setup.

bash

# 1. Quant (also provides serving/patches/ and serving/serve.sh)
Q="$(hf download Jon-Nielsen/__REPO__)"

# 2. Fork at the pinned commit (current public tip of the branch)
git clone --branch appmana/upstream-merge \
  https://github.com/AppMana/forks-vllm-consumer-nvidia-platforms.git
cd forks-vllm-consumer-nvidia-platforms
git checkout 760ced86b

# 3. Patches: upstream engine sync, then the consumer-NVIDIA fixes
git apply "$Q/serving/patches/0001-upstream-sync-20260906.patch"
git apply "$Q/serving/patches/0002-consumer-nvidia-fixes-20260906.patch"

# 4. Dependencies
python -m venv .venv && source .venv/bin/activate
pip install torch==2.13.0+cu130 \
  --extra-index-url https://download.pytorch.org/whl/cu130
pip install flash-mla==2.0.0+8ec3de6 \
  --extra-index-url https://appmana.github.io/forks-flash-mla-int/

# 5. Build and install (sm86 only — saves 3-5x build time)
MAX_JOBS=12 TORCH_CUDA_ARCH_LIST="8.6" pip install -e . --no-build-isolation

# 6. Serve — defaults are the recommended measured profile
# (TP4 x PP2, async scheduling, 512K context, ~1.0M-token KV pool)
VENV="$PWD/.venv" MODEL="$Q" bash "$Q/serving/serve.sh"

On a box with mixed PCIe widths, order ranks so the first PP stage gets the x16 cards, e.g. x16 = 0,1,2,7: CUDA_VISIBLE_DEVICES=0,1,2,7,3,4,5,6.

All engine fixes (prefill workspace reservation, allocator settings, graph-memory profiling opt-out, dense capture sizes) are baked into serving/serve.sh — see serving/README.md and serving/profiles.md for what each knob does and the alternative profiles.

Patches

Two anonymous diffs against the fork's public tip 760ced86b (branch appmana/upstream-merge), applied in order:

0001-upstream-sync-20260906.patch

Brings the engine to the post-merge state used for validation: 57 upstream/main commits (graph memory profiling default, Fast Start, MRV2 DBO, DSv4 fixes) plus conflict resolutions.

0002-consumer-nvidia-fixes-20260906.patch

The consumer-NVIDIA delta on top:

int8_ds_mla bounds-guarded cache insert kernels (PR-A port)
KV-offload IMA-safe host memory + block-id range checks (PR-B port)
mxfp4 w13 loader + conversion tool kernel block (PR-C port)
worst-case prefill K-gather workspace reservation + env-overridable VLLM_DSV4_PREFILL_CHUNK_SIZE (long-context workspace locked fix)
_vllm_fa3_C optional (Ampere builds produce no FA3 .so)

760ced86b + both patches equals commit 623739503 of the maintainer's line (verified in a throwaway worktree; modulo serving documentation). The previous recipe's three patches (expert weight loader, conversion kernel block, int8 prefill safety) are superseded — all three are contained in 0002.

Serving directory

serving/
  serve.sh                                          — launcher; defaults = recommended profile
  profiles.md                                       — measured profile matrix + envelope rules
  README.md                                         — recipe, knob explanations, known-good facts
  convert.sh                                        — re-run the conversion (tool in the patched fork)
  tests/                                          — bench harness behind profiles.md + card numbers
  checksums/                                      — sha256 of published shards (base/ablit)
  patches/0001-upstream-sync-20260906.patch         — upstream engine sync (745 KB)
  patches/0002-consumer-nvidia-fixes-20260906.patch — consumer-NVIDIA fixes (43 KB)

Below is the original README from deepseek-ai/DeepSeek-V4-Flash-0731, included for reference only. The encoding/ and inference/ folders it mentions are not part of this repository.

Original DeepSeek-V4-Flash-0731 README

DeepSeek-V4

Twitter Follow

Technical Report👁️

Introduction

DeepSeek-V4-Flash-0731 is the official release of DeepSeek-V4-Flash, superseding the preview version, with substantially enhanced agentic capabilities. It has the same model structure as DeepSeek-V4-Flash-DSpark, i.e. it comes with a speculative decoding module attached.

DeepSeek-V4-Flash-0731 outperforms DeepSeek-V4-Pro (Preview) on benchmarks listed below despite its far smaller activated parameter count, and is broadly competitive with the strongest proprietary models available.

Benchmark	DeepSeek-V4-Flash-0731	DeepSeek-V4-Flash (Preview)	DeepSeek-V4-Pro (Preview)	GLM-5.2	Opus-4.8
Terminal Bench 2.1	82.7	61.8	72.1	81.0	85.0
NL2Repo	54.2	39.4	38.5	48.9	69.7
Cybergym	76.7	38.7	52.7	-	83.1
DeepSWE	54.4	7.3	12.8	46.2	58.0
Toolathlon-Verified	70.3	49.7	55.9	59.9	76.2
Agents' Last Exam	25.2	15.8	16.5	23.8	25.7
AutomationBench Public	25.1	10.8	12.8	12.9	27.2
DSBench-FullStack †	68.7	37.0	41.8	61.8	71.6
DSBench-Hard †	59.6	25.8	31.1	54.5	71.7

Notes:

For the Code Agent tasks among the public benchmarks above, DeepSeek-V4-Flash-0731 is evaluated with the minimal mode of DeepSeek Harness (to be released) as the agent framework, using the max reasoning effort level with temperature = 1.0, top_p = 0.95.
† DSBench-FullStack is an internal full-stack development test set; DSBench-Hard is an internal test set of difficult coding-agent problems.

Chat Template

This release does not include a Jinja-format chat template. Instead, we provide a dedicated encoding folder with Python scripts and test cases demonstrating how to encode messages in OpenAI-compatible format into input strings for the model, and how to parse the model's text output. Please refer to the encoding folder for full documentation.

The reasoning_effort parameter now supports three levels — low, high, and max — which control how much deliberation the model spends before answering.

A brief example:

python

from encoding_dsv4 import encode_messages, parse_message_from_completion_text

messages = [
    {"role": "user", "content": "hello"},
    {"role": "assistant", "content": "Hello! I am DeepSeek.", "reasoning_content": "thinking..."},
    {"role": "user", "content": "1+1=?"}
]

# messages -> string
prompt = encode_messages(messages, thinking_mode="thinking", reasoning_effort="max")

# string -> tokens
import transformers
tokenizer = transformers.AutoTokenizer.from_pretrained("deepseek-ai/DeepSeek-V4-Flash-0731")
tokens = tokenizer.encode(prompt)

How to Run with vLLM

DSpark speculative decoding is enabled with a single flag — add --speculative-config with method: dspark to your vLLM launch command:

--speculative-config '{"method":"dspark","num_speculative_tokens":7,"draft_sample_method":"greedy"}'

For example, the command below serves the model with vLLM on a single 4×GB300 node. See the vLLM recipe for detailed instructions and other hardware configurations.

bash

vllm serve deepseek-ai/DeepSeek-V4-Flash-0731 \
  --trust-remote-code --kv-cache-dtype fp8 --block-size 256 \
  --data-parallel-size 4 --enable-expert-parallel \
  --moe-backend deep_gemm_mega_moe \
  --attention-config '{"use_fp4_indexer_cache": true}' \
  --speculative-config '{"method":"dspark","num_speculative_tokens":7,"draft_sample_method":"greedy"}'

How to Run with SGLang

Enable DSpark with --speculative-algorithm DSPARK and do not set a separate --speculative-draft-model-path as the target and draft weights therefore come from the same checkpoint. See the SGLang cookbook for detailed instructions, benchmarks and other hardwares configurations.

bash

sglang serve \
  --trust-remote-code \
  --model-path deepseek-ai/DeepSeek-V4-Flash-0731 \
  --tp 4 \
  --moe-runner-backend flashinfer_mxfp4 \
  --speculative-algorithm DSPARK \
  --mem-fraction-static 0.90 \
  --chunked-prefill-size 4096 \
  --swa-full-tokens-ratio 0.1 \

How to Run Locally

Please refer to the inference folder for detailed instructions on running DeepSeek-V4 locally, including model weight conversion and interactive chat demos.

For local deployment, we recommend setting the sampling parameters to temperature = 1.0, with top_p = 0.95 for agentic scenarios and top_p = 1.0 otherwise. For the high and max reasoning effort levels, we recommend a maximum output length of 384K tokens.

License

This repository and the model weights are licensed under the MIT License.

Citation

@misc{deepseekai2026deepseekv4,
      title={DeepSeek-V4: Towards Highly Efficient Million-Token Context Intelligence},
      author={DeepSeek-AI},
      year={2026},
}

Contact

If you have any questions, please raise an issue or contact us at service@deepseek.com.

Jon-Nielsen/DeepSeek-V4-Flash-0731-MXFP4-INT8

DeepSeek-V4-Flash-0731 MXFP4-INT8

What this is

How it was created

What to expect

How to serve

Patches

0001-upstream-sync-20260906.patch

0002-consumer-nvidia-fixes-20260906.patch

Serving directory

Original DeepSeek-V4-Flash-0731 README

Introduction

Chat Template

How to Run with vLLM

How to Run with SGLang

How to Run Locally

License

Citation

Contact

Jon-Nielsen/
DeepSeek-V4-Flash-0731-MXFP4-INT8