flint-nvfp4-coldgptq
NVFP4 quantization of RecursiveSI/flint (revision 2a247be), Recursive's
39.8B-total / ~2.5B-active mixture-of-experts model for coding agents. The checkpoint is 23.5 GB instead of 79.6 GB,
so one Blackwell GPU keeps most of its memory for KV cache.
What is quantized
- The 12,032 routed experts of MoE layers 2–48 (
gate_proj,up_proj,down_proj) are static W4A4 NVFP4: FP4 E2M1 weights in 16-element blocks with FP8 E4M3 block scales and FP32 global scales, in NVIDIA ModelOpt's per-expert layout (weight,weight_scale,weight_scale_2,input_scale). - Every other tensor is the unchanged BF16 source tensor: attention and its learned sinks, routers, shared experts,
the dense layers 0–1, norms, embeddings and
lm_head.
Evaluation
B300, SGLang 0.5.16 with flint_sglang 0.1.4 and the base repository's serve_b300.sh flags, using the model's default
sampling (temperature 1.0, top-p 0.95, top-k 20). Accuracy is the mean over all samples; generation length counts
completion tokens, reasoning included.
| Benchmark | Accuracy, BF16 → NVFP4 | Generation length p50 / p90 (tokens), BF16 → NVFP4 |
|---|---|---|
| GSM8K, 1,319 questions | 96.1 → 96.0 | 451 / 2,796 → 459 / 3,004 |
| GPQA Diamond, 198 questions × 3 samples | 69.2 → 68.9 | 6,718 / 30,918 → 7,440 / 30,553 |
| AIME 2026, 30 problems × 16 samples | 84.4 → 83.8 | 7,927 / 32,768 → 8,294 / 32,768 |
GSM8K completions are capped at 16,384 tokens and GPQA and AIME at 32,768. The cap was reached by 8.8% / 7.7% of GPQA samples and 13.3% / 14.2% of AIME samples (BF16 / NVFP4), so AIME's p90 is the cap for both. In GPU memory the NVFP4 weights take 23.6 GB, against 74.2 GB for BF16.
Usage
NVFP4 needs a Blackwell GPU; this checkpoint was validated on B300. Install the Flint SGLang kit from the base
repository (sglang/install.sh, or its Dockerfile), then point the kit's serve script at this checkpoint. SGLang reads
the ModelOpt NVFP4 configuration from config.json, and the kit's default flags (FA4 attention,
flashinfer_trtllm_routed MoE) work unchanged.
hf download FutureMLS-Lab/flint-nvfp4-coldgptq --local-dir flint-nvfp4-coldgptq
hf download RecursiveSI/flint --include "sglang/*" --local-dir flint-kit
MODEL=$PWD/flint-nvfp4-coldgptq bash flint-kit/sglang/serve_b300.sh
Use the chat template and sampling defaults shipped with the checkpoint, as described in the base model card.
License
Apache-2.0, the same license as the base model. See RecursiveSI/flint for the model's intended uses and limitations.