What was re-measured for this version (2026-09-07, temperature 0, thinking off, same serving config as bf16)
Quantization changes abstention behavior. So instead of copying over the bf16 card's
figures, we re-measured them on this checkpoint.
Table with columns: Axis, bf16 original, This model (NVFP4), How to read it| Axis | bf16 original | This model (NVFP4) | How to read it |
|---|
| KoBBQ ambiguous-context abstention (8,139) | 92.8% | 89.5% | 3.3pp lower. Misses the pre-registered target of 93%, +23.8pp over EXAONE 4.5's 65.7% |
| Change in disambiguated-context accuracy (vs. base 90.66) | −2.1pp | −0.9pp | Less over-abstention (within the −3pp threshold) |
| Conditional bias (among answered items) | 0.861 | 0.848 | Both miss the pre-registered target of 0.60 (structural — see the bf16 card) |
| Identity probe (8-language holdout, n=240) | 96.2% | 95.8% | 1-item difference |
| MMLU English 1,000 (thinking off) | 80.9% | 80.0% | Within detection limit |
| Thinking-mode empty responses (100) | 0 | 0 | No format defect |
| Korean human-likeness pairwise win rate (n=175) | +14.3pp | +10.3pp | Judge uncalibrated, direction only |
| HumanEval (executed, same run, n=148) | 97.1% | 94.6% | −2.5pp, 4-item difference, within detection limit |
| KMMLU 1,000 (same run) | 52.3% | 54.4% | +2.1pp |
| Instruction following 100 (deterministic checker) | 79% | 81% | Equivalent |
In one line: it abstains slightly less and also over-abstains slightly less — behavior
similar to shifting β a bit toward 0.2. If abstention rate is the top priority, use
bf16 or W4A16; if memory and speed on Blackwell come first, use this version. Capability
gates (coding·KMMLU·instruction) were re-measured in the same run with bf16 as the
reference arm and entered into the table above. The difference from the bf16 card's
absolute values is because the runs differ; read the comparison only within the same
run.
Quantization recipe
llm-compressor 0.13.0 GPTQ · calibration 1,024 samples × 2,048 tokens (chat format, 25%
Korean) · dampening 0.01 · actorder static · scheme NVFP4 (MLP) + FP8_DYNAMIC (attention)
· ignore: vision/visual, lm_head, embed_tokens, linear_attn.in_proj_a/b. Took 46
minutes (1x B200). Metadata is in quantize_meta.json; the actual group and ignore lists
are in config.json's quantization_config, verbatim.
Serving
Blackwell (SM100+: B200·GB200·RTX 50) only. There is no NVFP4 kernel on Hopper or below.
vllm serve ThakiCloud/Qwen3.8-27B-Human-KO-Safety-NVFP4 \
--max-model-len 32768 --kv-cache-dtype fp8 --enable-prefix-caching
vLLM ≥ 0.28 auto-detects the scheme from config.json, so there is no need to pass
--quantization separately. DFlash drafter speculative decoding is not recommended on
NVFP4, since a single-stream penalty (0.71-0.82x) has been measured.
Limitations
- The safety axis was measured with KoBBQ alone, and the table above is from a single
build of this quantized checkpoint. Given the noise between requantization builds (our
measured GSM8K figure is 3.56pp), a difference within 3pp is not attributed to the
treatment.
- The abstention rate of 89.5% differs from the bf16 card's 92.8%. Do not cite the bf16
figure for this model.
- Other limitations and data provenance are the same as the bf16 card and
DATA_PROVENANCE.md.
License
Apache-2.0 (same as Qwen/Qwen3.8-27B). See LICENSE · NOTICE.