Rainbow/garbage output on RTX 5090 with diffusers

#14
by tomphillips9 - opened

I'm getting rainbow/garbage output when running the official Z-Image example with diffusers on an RTX 5090 (Blackwell), Windows. Same code from the model card works in terms of running, but the decoded image is wrong.

Setup

  • GPU: NVIDIA GeForce RTX 5090
  • OS: Windows
  • Python: 3.12, in a venv (not global)
  • PyTorch: 2.7.1+cu128
  • diffusers: 0.37.0.dev0

What I'm running

The exact example from the model card (prompt, ZImagePipeline.from_pretrained("Tongyi-MAI/Z-Image", torch_dtype=torch.bfloat16), then pipe(...) with num_inference_steps=30, guidance_scale=4, cfg_normalization=False, height=512, width=512). Image saves without error but looks like rainbow/noise.

What I've already tried

  • Triton / Sage Attention: Not installed in this env. importlib.util.find_spec("triton") and "sageattention" are both None. So the pipeline is using default PyTorch attention.
  • TORCHAO_DISABLE_INTMM=1: Set before running; no change. Still get torchao.kernel.intmm warning and rainbow output.
  • fp32: With torch_dtype=torch.float32 the output is the same rainbow junk.
  • With a step callback: NaNs first appear at denoising step 0 (first transformer forward). So the issue is the Z-Image transformer on RTX 5090, not the VAE or quantization.
  • Z-Image Turbo (local, same 5090 setup) runs fine; the issue appears specific to the base Z-Image model.

Question

Is Z-Image (base) with the official diffusers pipeline known to work on RTX 5090 / Blackwell? If yes, what environment (PyTorch/diffusers versions, dtype, any env vars or flags) are you using? If there’s a known workaround (e.g. disable a backend, use a specific diffusers version), I’d appreciate a pointer.

Thanks.

tomphillips9 changed discussion title from Z-Image (base) rainbow/garbage output on RTX 5090 with diffusers to Rainbow/garbage output on RTX 5090 with diffusers

Can you try with CUDA 13

After spending half the day on this, it turns out the repo just hadn't downloaded correctly. File sizes and everything looked complete, but it was corrupted and redownloading fixed the issue. False alarm, sorry!

tomphillips9 changed discussion status to closed

This thread is resolved: the root cause was a corrupted download. Redownloading the model fixed the rainbow/garbage output. Not a pipeline bug.

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