Qwen3.8-27B-NVFP4

A competitive, efficient NVFP4 build that matches or leads the alternative build across the measured benchmarks, stays measurably closer to the original BF16 model, and delivers faster single-stream generation on the tested hardware.

Highlights

• Matches or leads unsloth/Qwen3.8-27B-NVFP4 across CMMLU, C-Eval, and non-thinking MMLU-Pro, with MMLU-Pro essentially at parity.
• Records 0.0265 KL divergence from BF16 versus 0.0391 for the competing build—about 32% lower and measurably closer to the original BF16 output distribution.
• Reaches 61.2 tokens/s single-stream versus 58.5 for the competing build and 27.4 for BF16 on the tested configuration—about 2.2× BF16.
• Delivers near-parity aggregate throughput at 32 concurrent requests: 1284 tokens/s versus 1292; higher concurrency tends to favor the competing build's FP4 kernel path.
• Downloads at 23.29 GB versus 23.4 GB for the competing build.
• NVFP4 4-bit weights for vLLM serving on NVIDIA Blackwell GPUs.

Results

Metric	BF16 baseline	kyaky/Qwen3.8-27B-NVFP4	unsloth/Qwen3.8-27B-NVFP4	Result
CMMLU accuracy ↑	72.03	73.55	70.76	+2.80 pp vs competitor
C-Eval accuracy ↑	74.07	75.93	73.63	+2.30 pp vs competitor
MMLU-Pro accuracy ↑, non-thinking	75.43	77.14	76.57	Essentially at parity with competitor
KL divergence vs BF16 ↓	0 (reference)	0.0265	0.0391	About 32% lower than competitor
Download size ↓	—	23.29 GB	23.4 GB	0.11 GB smaller

All comparisons use the same evaluation conditions. Small differences from the BF16 reference should be treated as evaluation variation, not as evidence that this build surpasses the base model's capabilities.

Performance (measured on 1 × NVIDIA RTX PRO 6000 only)

Measured on 1 × NVIDIA RTX PRO 6000 (Blackwell) using vLLM 0.25.1 with greedy decoding and an FP8 KV cache at 8K context. Workload: 256-token generations; single-stream is the mean of 3 runs, concurrent is 32 simultaneous requests. Values are tokens/second and apply only to this tested configuration; they should not be assumed to generalize to other hardware or serving setups.

Metric	BF16 original	kyaky/Qwen3.8-27B-NVFP4	unsloth/Qwen3.8-27B-NVFP4	Result
Single-stream generation speed (tokens/s) ↑	27.4	61.2	58.5	+4.6% vs competitor; about 2.2× BF16
Aggregate throughput at 32 concurrent requests (tokens/s) ↑	648	1284	1292	Near-parity at this concurrency; both roughly 2× BF16; higher concurrency tends to favor the competing build's FP4 kernel path

Serve with vLLM

vllm serve kyaky/Qwen3.8-27B-NVFP4 --trust-remote-code

NVFP4 requires an NVIDIA Blackwell GPU, such as an RTX 50-series or RTX PRO 6000-class GPU, and is served through vLLM.

Intended use

Choose this release for a well-rounded 23.29 GB NVFP4 build with competitive benchmark retention, closer measured BF16 fidelity, and strong serving performance on the tested Blackwell configuration. It leads the competing build on CMMLU and C-Eval, remains essentially at parity on non-thinking MMLU-Pro, is faster in single-stream generation, and provides near-parity aggregate throughput at 32 concurrent requests.

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kyaky/Qwen3.8-27B-NVFP4 is an independent NVFP4 release derived from Qwen/Qwen3.8-27B. Review the base model card for capabilities, acceptable use, and license terms.