rajasingh012/gemma-4-12b-it-quark-w8a8-int8

Gemma-4-12B-it-Quark-W8A8-INT8

W8A8 INT8 quantized version of google/gemma-4-12b-it using AMD Quark, produced as part of the RetailConcierge AMD AI DevMaster 2026 submission.

Model Details

Quantization Scheme

How to Use

With vLLM (Recommended)

# Start the server (single AMD MI300X is enough)
vllm serve rajasingh012/gemma-4-12b-it-quark-w8a8-int8 \
    --tensor-parallel-size 1 \
    --max-model-len 32768 \
    --gpu-memory-utilization 0.9 \
    --quantization quark \
    --trust-remote-code \
    --enable-prefix-caching \
    --enable-chunked-prefill

# Chat completion
curl http://localhost:8000/v1/chat/completions -H "Content-Type: application/json" -d '{
  "model": "rajasingh012/gemma-4-12b-it-quark-w8a8-int8",
  "messages": [{"role": "user", "content": "Recommend a pair of wireless earbuds under 5000 rupees."}],
  "max_tokens": 512,
  "temperature": 0.7
}'

Requires vLLM >= 0.26 (the --quantization quark loader). Tested on vLLM 0.26.0+rocm723 (AMD ROCm wheel) with --tool-call-parser gemma4.

Hardware Requirements

• —Minimum: 1× GPU with ≥48 GB VRAM (e.g., AMD MI300X / MI350X, NVIDIA A100-80G).
• —Quantized weights measure ~12.5 GiB on GPU, leaving ample KV cache headroom.

Quantization Details

This model was quantized using AMD Quark's per-token per-channel INT8 scheme (W8A8):

• —Weight quantization: INT8 per-channel (one scale per output channel), symmetric, static.
• —Activation quantization: INT8 per-token (one scale per token), symmetric, dynamic (computed at inference time, so no calibration data needed).
• —Excluded layers: model.vision_embedder.*, model.embed_vision.embedding_projection, model.embed_audio.embedding_projection (vision/audio modalities preserved in BF16). lm_head shares storage with embed_tokens (tie_word_embeddings: True).
• —Export: real INT8 weights with BF16 scales (no fake-quant, no zero-point), Quark 0.12 export_safetensors.
• —Post-export fixup (required): Quark 0.12 exports some vision keys under names vLLM's gemma4_unified loader does not map (embed_vision.multimodal_embedder.*, embed_vision.patch_*). The fixup renames them to the expected layout and copies chat_template.jinja into the output (vLLM 400s chat requests without it). The fixup is automated in the RetailConcierge repo (scripts/_quark_fix_vllm_keys.py) and is required for any Gemma 4 Unified checkpoint.

Reproduce Quantization

Full reproducible recipe in the RetailConcierge repo, scripts/ folder:

# On the AMD GPU droplet (see scripts/README.md for full lifecycle)
bash /root/quantize_int8.sh --model google/gemma-4-12b-it

The script handles: preflight (Quark version, transformers >= 5.10.1 for Gemma4UnifiedForConditionalGeneration, BF16 source location), the Quark W8A8 quantize, the post-export key fixup, and output verification. Recipe provenance: nameistoken/Gemma-4-31B-it-Quark-W8A8-INT8 (−0.08pp GSM8K on the 31B dense class); the 12B Unified run is a fresh quantization of the same scheme.

Accuracy

Caveat: the −0.08pp GSM8K figure published on the 31B dense baseline was measured on the older Gemma4ForConditionalGeneration class. The 12B Unified class uses a different multimodal embedding layout; accuracy for this checkpoint is validated via the RetailConcierge tool-call accuracy gate (extractbrief → searchcatalog → finalize_recommendations pass rate vs BF16), not yet via GSM8K. Treat as a fresh quantization until independently benchmarked.

Citation

If you use this model, please cite the original Gemma 4 release:

@misc{google2026gemma4,
  title  = {Gemma 4},
  author = {Google DeepMind},
  year   = {2026},
  url    = {https://huggingface.co/google/gemma-4-12b-it}
}

License

This model is released under the [Apache License 2.0](https://www.apache.org/licenses/LICENSE-2.0), following the Gemma 4 license under which the upstream google/gemma-4-12b-it weights are distributed by Google DeepMind.

This is a quantized derivative of google/gemma-4-12b-it. Per Apache 2.0 §4:

• —Modified files (the INT8-quantized model.safetensors and the appended quantization_config block in config.json) carry this notice as part of the model card.
• —Original copyright and attribution notices from the base model are preserved (see NOTICE).
• —A copy of the Apache 2.0 license text is included as LICENSE.

Original weights © Google DeepMind. Quantization performed by the model author; no warranty of any kind is provided (see LICENSE §7–8).