Qwen-Image-Edit-2511 — INT4 tensorwise W4A4 (+ConvRot, mixed int8 fallback)
W4A4 quantization of Qwen-Image-Edit-2511: weights in packed signed INT4 (2/byte) with group-256 regular-Hadamard ConvRot rotation (arXiv 2512.03673), activations rotated online and dynamically quantized to INT4 inside the kernel. Calibration-free.
Mixed-precision quality recipe (validated end-to-end): 480 layers INT4 + 359
sensitive layers (attention value/output projections and the adaLN modulation
Linears — critical) stored as stock int8_tensorwise in the same checkpoint.
The __index_timestep_zero__ sentinel is included (2511 reference-image mode).
Samples
Same seed/prompt edit samples, BF16 top vs INT4-mixed bottom.
⚠️ Runtime requirement
Needs the int4_tensorwise runtime, which is not in any released ComfyUI /
comfy-kitchen yet. In-flight:
comfy-kitchen PR #63
(kernels + layout) and the
ComfyUI loader branch
— to try this checkpoint today, run that ComfyUI branch with the PR's
comfy-kitchen branch on PYTHONPATH (or installed). On a stock release it
fails with a clear "format not available" error.
Measurements
Quality (L4, 20-step edit sample, mean over 4 prompts, PSNR vs bf16-sentinel):
| checkpoint | size | PSNR |
|---|---|---|
| int8_tensorwise | 20.0 GB | 30.05 dB |
| this model (int4 mixed) | 14.9 GB | 26.58 dB |
| bf16 | 40 GB | — |
Speed (NVIDIA L4 / SM 8.9 — native INT4 tensor cores; 20-step image, steady state, same-session comparison, fused ConvRot + rank-one s4 MMA kernel):
| path | s/image |
|---|---|
| this model (int4 mixed) | 87.1 |
| int8_tensorwise (CUDA kernels) | 93.1 |
| bf16 | 114 |
Reproduce
comfy-quants export-model-int4-tensorwise \
--config configs/qwen_image_edit_2511_int4_tensorwise_mixed.yaml \
--source /path/to/Qwen-Image-Edit-2511/transformer \
--out qwen_edit_2511_int4tw_mixed.safetensors
Produced by comfy-quants (branch
feat/int4-tensorwise). A higher-quality variant (+MLP down-projections at int8,
17.2 GB / 27.19 dB) is one config edit away — see the config comments.