DeepSeek-V4-Flash-0731-GGUF

DeepSeek-V4-Flash-0731 GGUF — one RTX PRO 6000 96GB, no offload

Three imatrix-guided quants, plus the DSpark draft head for speculative decoding. Every variant keeps all tensors on a single 96 GB card — no CPU expert offload, no second GPU, no layer spill.

Which one do I want?

• IQ2_XS — best weights, if you do not need past ~384K.
• IQ2_XXS — full 1M at maximum quality.
• IQ2_XXS-slim + DSpark draft — full 1M at ~1.7x decode. Recommended daily driver.

The three form one monotonic ladder: each step down costs roughly 1 point of top-1 agreement with the unquantized master. Slim gives up 1.03 points against IQ2_XXS to free the 4.3 GiB the draft head needs.

Recipes

Imatrix-guided (606,208 calibration tokens at 8K context, 100% expert-slice coverage). None use IQ1_S/IQ2_S/IQ3_S, whose CUDA kernels are broken on Blackwell (sm_120).

Slim keeps full precision on the first and last ten blocks, where quantization damage concentrates, and spends the savings only in the middle of the stack.

general.file_type reports the base type passed to llama-quantize, not the mixture actually present — trust the table, not that field.

Settings for one RTX PRO 6000 96GB

Needs a llama.cpp build with DeepSeek-V4 support. The draft additionally needs b10236 or newer (upstream #25784 and #26452).

Recommended — slim + DSpark at full 1M:

CUDA_VISIBLE_DEVICES=0 llama-server \
  --model DeepSeek-V4-Flash-0731-IQ2_XXS-slim-00001-of-00004.gguf \
  --spec-draft-model DeepSeek-V4-Flash-0731-DSpark-Q2_K.gguf \
  --spec-type draft-dspark --spec-draft-ngl 99 --spec-draft-n-max 3 \
  --device CUDA0 --split-mode none -ngl 999 --fit off \
  --ctx-size 1048576 -fa on -b 2048 -ub 512 -np 1 \
  --jinja --temp 1.0 --top-p 1.0 --min-p 0.0

Point llama.cpp at the first shard; it finds the rest automatically.

-ub 2048 does not fit at 384K on IQ2_XS, and -ub 1024 does not fit at 1M with the draft attached. If the card also drives a display, take one step down in ubatch for roughly 740 MiB more headroom.

Settings that matter

• --spec-draft-n-max 3, not 5. The draft advertises block_size 5, but drafting 3 is 27% faster: n_max 2/3/4/5 → 130/139/113/109 tok/s.
• The draft must share a GPU with the target. It borrows the target's tok_embd and output projection, so putting it on a second device aborts at graph allocation.
• Draft precision does not affect speed. Q2_K, Q3_K and the native MXFP4 draft all decode within 1.3% of each other; the smallest is published because the freed VRAM is worth more in the target.
• --fit off and --split-mode none make a bad configuration fail loudly instead of silently spilling to CPU and costing most of your speed.
• f16 KV. Quantized KV is unnecessary at 1M with slim, and costs ~4% decode.
• Reasoning is always on. Send max_tokens comfortably above any --reasoning-budget, or you get finish_reason: length and empty content whether or not the model solved the task.

Validation

IQ2_XXS-slim at 1M with the draft attached: 27/27 depth probes exact — verbatim retrieval plus multi-hop reasoning combining facts planted at 10%, 50% and 90% depth, at 6K / 32K / 131K / 262K / 524K and 991,046 tokens. Draft acceptance does not decay with depth (81% at 990K against 74–87% at 6–32K). IQ2_XXS was separately validated with exact retrieval from a 989,987-token prompt.

KL divergence is measured against the release-faithful MXFP4/BF16 master over wikitext-2 (-c 512 --chunks 100). Perplexity is deliberately not reported: it can rank a lower-bit quant above its own higher-bit reference, so it does not measure quantization damage.

A near-1M prefill takes roughly 55 minutes on this hardware — these are large-but-not-maximal-prompt configurations, not million-token batch processors. Once a long context is loaded, follow-up questions reuse the cached prefix and cost seconds.

Known issue: reasoning length on recent llama.cpp

On builds including upstream dee2a846b (ggml : adjust logic for offloading ops to weight's backend, #25832), this model's reasoning runs roughly 5x longer and degenerates into repetition — 13,449 reasoning characters versus 2,613 on the immediately preceding commit, identical prompt at temperature 0. It is a graph-scheduling change affecting DeepSeek-V4 numerics, bisected to that single commit, and it reproduces on every quant here. It is unrelated to quantization. The DSpark draft requires a build newer than this, so the two cannot currently be separated.

Files

sha256sum -c SHA256SUMS

Attribution

Base model and architecture by DeepSeek-AI. Quantization, calibration and single-GPU validation by prometheusAIR. This quant inherits the capabilities, limitations, risks and MIT license of the base model; you are responsible for evaluating outputs and applying safeguards appropriate to your application.

Please read the original model card for architecture details, recommended sampling and the base model's own limitations.

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