Run it
You need Linux x86_64, two visible SM120 GPUs, Docker with the NVIDIA
Container Toolkit and about 170 GB of disk.
pip install -U huggingface_hub
export MODEL_DIR=/srv/models/GLM-5.3-Flash-W4A16-NVFP4-K32-Experts-FP8-WO
HF_XET_HIGH_PERFORMANCE=1 hf download ormandj/GLM-5.3-Flash-W4A16-NVFP4-K32-Experts-FP8-WO --local-dir "$MODEL_DIR"
git clone https://github.com/ormandj/sglang-glm53-flash-sm120
cd sglang-glm53-flash-sm120
export IMAGE=ghcr.io/ormandj/sglang-glm53-flash-sm120:v0.1.1
export CACHE_DIR=/srv/cache/sglang-glm53-flash-sm120-v55
./examples/serve-glm53-flash.sh
The first boot compiles kernels into CACHE_DIR and takes about 10 to 20
minutes; later boots take about 8. The server is OpenAI-compatible on port
8000 with model name glm-5.3-flash. Measured throughput, capacity and
quality are in the repository's
README.
What is quantized
- Routed experts in layers 3 through 45: ModelOpt W4A16 NVFP4, signed E2M1
packed weights, E4M3FN scales over K=32, BF16 activations.
- 317 attention and shared-expert projections in layers 0 through 44: E4M3
block-FP8 weight-only with FP32 inverse scales over 128x128 blocks.
- Kept in source precision: the layer 45 MTP draft weights (quantizing them
silently collapses speculative acceptance to zero), the DSA indexer, the
vision tower and projector, embeddings, LM head, routers, norms and
ineligible linears.
- Tensor payload: 177,995,252,856 bytes in 90 safetensors shards.
Reconstruction against the BF16 source: routed experts aggregate relative L2
0.0851 (minimum matrix cosine 0.9949); FP8 tier aggregate relative L2 0.0225
(minimum cosine 0.9996). The full tensor selection, producer pins,
per-tensor measurements and per-shard hashes are in
quantization-manifest.json, reconstruction-metrics-*.json and
model-sha256.json.
Runtime compatibility
The checkpoint uses the modelopt_mixed metadata contract and needs the
pinned SGLang and FlashInfer integration in the image above
(--quantization modelopt_mixed, shared-expert fusion disabled). Upstream
Transformers, vLLM and SGLang releases do not load it correctly today.
Integrity
The publishing build refuses to upload unless its model files reproduce the
served artifact exactly:
config.json: 00cf7f0ae5cbc1ca1593376730aa52dd918b59cab28552c61e9d8e3fd7a19d20
model.safetensors.index.json: 944bb41dd3dc2b6fde6b37465b9d9f7743ea89002302b7c38a87e0242270554d
model-sha256.json: 655a9b802f0629d1067f2350ee4e6d4c288c642846f2b1955760000ebf9bdfa5
The last file holds the SHA-256 digest of every model shard.
License and attribution
The source checkpoint is MIT-licensed. See the included license and the
upstream model card for the original model's usage guidance, limitations
and citation.