GLM-5.3-Flash — NVFP4 (JANGQ-AI)

~330B MoE (288 routed experts) · NVFP4 experts · FP8 MLA attention · Blackwell / GB10 · TP2

Runtime status: not yet validated end-to-end. This is a compressed-tensors mixed-precision bundle (NVFP4 experts + FP8 attention). vLLM ≥ 0.31 supports Glm5NextForConditionalGeneration and the compressed-tensors NVFP4 path on Blackwell, but this exact bundle has not yet been served and checked for coherent output. Until that is done, treat it as a candidate, not a release. Native MTP (layer 45) is not included — pair with an external drafter (DFlash2) if you want speculative decoding.

What this is

An NVFP4 requantization of zai-org/GLM-5.3-Flash (from the BF16 release), targeted at NVIDIA Blackwell (RTX 50 / GB10 / DGX Spark). Built with llm-compressor 0.14 / compressed-tensors 0.19 / transformers 5.17.

Component Precision
Routed experts (42 MoE layers × 288 × gate/up/down) NVFP4 — E2M1, group 16, FP8-E4M3 block scales + FP32 global scale, static calibrated input scales
MLA attention q_a/q_b/kv_a/o_proj (layers 3,7,…,43) FP8 E4M3 per-channel weights, dynamic per-token activations
KDA linear attention (34 layers), DSA indexer, router gates, shared experts, dense MLP (layers 0–2), embeddings, lm_head, vision tower BF16 (unchanged)
  • 189.1 GB on disk (176.1 GiB), 10 shards — fits TP2 across two 128 GB GB10 nodes with ~40 GiB/node left for KV cache.
  • Vision tower preserved in BF16 (multimodal input intact).
  • Verified from the safetensors headers: 36,288 packed expert matrices (42 × 288 × 3), 44 FP8 attention matrices.

Quality (teacher-forced, vs. the BF16 source)

40 held-out conversations (never seen in calibration; 16 long max-effort reasoning traces, 8 short reasoning, 8 cyber-security Q&A, 8 raw coding prompts), 52,143 scored tokens, per-token KL(BF16 ‖ NVFP4) and top-1 agreement:

Slice Tokens KL mean KL median p95 p99 Top-1
All 52,143 0.146 0.0063 0.35 3.43 91.6 %
Long max-effort reasoning 32,752 0.076 0.0049 0.13 1.35 93.8 %
Short reasoning 8,059 0.045 0.0019 0.15 0.62 94.5 %
Cyber-security Q&A 5,079 0.276 0.049 1.04 5.73 82.0 %
Raw coding prompts 6,253 0.541 0.011 3.00 11.6 84.3 %

Reading: the typical token is near-lossless and reasoning text is clean; the mean is dominated by a ~1–2 % tail of tokens (mostly raw code / security prompt text) where quantization flips expert routing. Caveat: these numbers were measured on the bundle's weights dequantized to BF16 — i.e. weight error only. The static NVFP4 activation scales are not simulated here; a real w4a4 runtime adds some activation error on top.

Calibration

RTN (min-max) NVFP4 with static activation-scale calibration; every routed expert saw every calibration token (moe_calibrate_all_experts). 225 conversations / 156k tokens rendered through the model's own chat template at reasoning_effort max/high: GLM-5.3-Flash-authored reasoning traces, wide-language coding, security, agentic/tool-calling and general prompts. Recipe shipped as recipe.yaml.

Recommended generation config

from openai import OpenAI
client = OpenAI(base_url="http://127.0.0.1:8000/v1", api_key="EMPTY")
resp = client.chat.completions.create(
    model="glm-5.3-flash",
    messages=[{"role": "user", "content": "Find the bug and fix it."}],
    temperature=1.0, top_p=0.95, max_tokens=16384,
    extra_body={"chat_template_kwargs": {"reasoning_effort": "max"}},   # low | high | max (default max)
)

Upstream sampling: temperature=1.0, top_p=0.95. Reasoning effort is a three-tier control in the chat template; max is the default when unspecified.

Credits

Quantized and evaluated by Jinho Jang (eric@jangq.ai) · JANGQ-AI · 2026-10-11. License: inherits the base model's license.

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