How to run
Compatible with vLLM, with no conversion step:
pip install "vllm>=0.27"
vllm serve QUASAR-QAT/Qwen3.8-27B-QUASAR-NVFP4 \
--max-model-len 262144 \
--gpu-memory-utilization 0.85 \
--speculative-config '{"method": "mtp", "num_speculative_tokens": 2}'
On a 32 GB card such as an RTX 5090, lower the context to --max-model-len 65536.
Requires an NVIDIA GPU with FP4 support (Blackwell, compute capability 10.0+).
Quality and size comparison
Two other public NVFP4 builds of this model, evaluated under the same setup (GPQA-Diamond: 2 runs, n=396; AIME'26: 3 repeats, n=90). Bold = best among the NVFP4 builds.
Table with columns: Model, Size, NVFP4 linears, GPQA-D, AIME'26| Model | Size | NVFP4 linears | GPQA-D | AIME'26 |
|---|
| QUASAR (this model) | 19.7 GB | 496/496 | 90.91 | 100.0 |
| BF16 original | 55.6 GB | — | 91.41 | 100.0 |
| Unsloth NVFP4 | 23.4 GB | 168/496 | 89.39 | 97.78 |
| Inferact NVFP4 | 26.4 GB | 304/496 | 87.63 | 96.67 |
Training
One epoch of loss-aware NVFP4 quantization-aware distillation against the frozen BF16
teacher: global batch size 32, learning rate 1e-6, 2446 steps.
Citation
arxiv.org/abs/2608.13966
@article{counathe2026quasar,
title={QUASAR: Lowering the Loss Floor of Quantization-Aware Training with Loss-Aware Reconstruction},
author={Counathe, Vincent and Athiwaratkun, Ben and De Sa, Christopher and Zhang, Tianyi},
journal={arXiv preprint arXiv:2608.13966},
year={2026}
}