Qwen3.8-Flash-Next-NVFP4-W4A16

Built with Qwen.

Weight-only NVFP4 quantization of the routed MoE experts of Qwen/Qwen3.8-Flash-Next. Activations stay at 16-bit.

What is quantized

Scheme NVFP4, 4-bit weights, group size 16, BF16 activations (W4A16)
Scope routed experts of the 48 text MoE layers — 120.8B params
Tool NVIDIA TensorRT Model Optimizer 0.46.0
Calibration data-free (algorithm: max)
Size 169 GiB, down from 336 GiB BF16

Everything else stays in BF16: attention, Gated DeltaNet linear attention, QSA indexer, shared experts, routers, hyper-connections, PLE n-gram tables, MTP head, vision tower, and lm_head.

Parameter breakdown

The model is 48 text layers, hidden size 2560, 512 experts per layer with top-10 routing and moe_intermediate_size 640. The routed experts are stored as fused 3-D tensors (mlp.experts.gate_up_proj (512, 1280, 2560) and mlp.experts.down_proj (512, 2560, 640)) and account for 120.8B of the ~125B main-model parameters — 96.6% of it.

Separately, the per-layer-embedding (PLE) n-gram tables are 128 shards of (2500012, 160), or 51.2B parameters / 97.7 GiB in BF16. They are not quantized here and are copied through byte-for-byte from the source checkpoint.

The parameter count shown in the sidebar is derived from the packed tensors and understates the real total.

Serving

SGLang has day-0 support for qwen4_exp and can serve this architecture today. vLLM support is not merged yet (vllm-project/vllm#53896).

Single-GPU serving needs the 97.7 GiB PLE table offloaded to host RAM (vllm-project/vllm#53899 adds VLLM_PLE_CPU_OFFLOAD=1 for vLLM). With PLE offloaded, the on-GPU weights are roughly 60 GiB.

We have not validated serving end to end yet. Measured configurations — GPU, tensor-parallel size, achievable max-model-len, and required engine flags — will be published here once we have run them.

Reproduction

Quantized with modelopt's NVFP4_EXPERTS_ONLY_CFG, modified to disable the expert input quantizers so activations remain 16-bit. The model is loaded with accelerate offload so that export_hf_checkpoint takes modelopt's streaming writer path, mtq.compress is applied before export, and the PLE tables are excluded from the export and restored afterwards from the source shards. This keeps peak host memory low enough to run the whole job on a single 96 GB GPU node with 160 GB of RAM.

License

Released under the Qwen Community License (see LICENSE). Built with Qwen.

Downloads last month
70
Safetensors
Model size
117B params
Tensor type
I64
·
BF16
·
U8
·
Inference Providers NEW
This model isn't deployed by any Inference Provider. 🙋 Ask for provider support

Model tree for MESHIVEAI/Qwen3.8-Flash-Next-NVFP4-W4A16

Quantized
(161)
this model