Scaling Muon for Diffusion Transformers
TL;DR - Periodic Row-wise Muon makes the Muon optimizer more practical for training Diffusion Transformers at 1.3B–15B parameters. It preserves Muon’s generative-quality gains while substantially reducing optimizer computation, communication, and total training time.
- Muon improved best observed generative quality by 12.9–19.1% over AdamW across tested model scales.
- The proposed method runs the full five-step Newton–Schulz spectral update only every (K) steps, using cheaper row-wise constrained updates between refreshes.
- A sharding-aware distributed implementation reduces optimizer time by 46.9–54.3%, step time by 15.7–24.3%, and logical communication volume by 66.7%.
- It reached its best generative quality with 33.7–64.8% less active training time than vanilla Muon, while staying within 0.5% quality on 1.3B–4B models and improving quality by 4.5% at 9B.