arXiv Computer Vision

Why DiT Models Underperform as Representation Learners without Long Skip Connections

The paper investigates why Diffusion Transformers (DiT) produce weaker features for vision tasks compared to their strong generative performance. Through controlled training, the authors demonstrate that incorporating long skip connections (LSCs) significantly improves feature quality. They explain that LSCs allow diffusion noise to bypass the main backbone, preventing noise pollution of image signals and aligning the architecture more closely with the diffusion objective.

arXiv AI
Jun 17

Rethinking Cross-Layer Information Routing in Diffusion Transformers

arXiv:2605. 20708v2 Announce Type: replace-cross Abstract: Diffusion Transformers (DiTs) have become a de facto backbone of modern visual generation, and nearly every major axis of their design -- tokenization, attention, conditioning, objectives, and latent autoencoders -- has been extensively revisited.

By Chao Xu, Maohua Li, Qirui Li, Yixuan Xu, Yanke Zhou, Yunhe Li, Cuifeng Shen, Hanlin Tang, Kan Liu, Tao Lan, Lin Qu, Shao-Qun Zhang
arXiv Computer Vision
Sep 7

Importance-Aware Low-Rank Distillation of Diffusion Transformers

The paper introduces SVDtrunc, a two‑step block‑level compression method for Diffusion Transformers (DiTs) that allocates ranks across blocks, applies truncated SVD to the least important ones, and then fine‑tunes all blocks with modular knowledge distillation and a rectified‑flow objective. Experiments on FLUX.dev show that SVDtrunc achieves near‑full performance at 68% of the original parameters and remains competitive even at 57%, outperforming all competing approaches on GenEval, HPSv2, and DPG benchmarks. The method also works well without fine‑tuning, complementing step distillation and offering a practical path to efficient large‑scale generative models.

By Denis Zavadski, Sebastian Heid, Damjan Kal\v{s}an, Stefan Roth, Carsten Rother
arXiv Machine Learning
Oct 8

Residual-Stream Burden Shapes Representation Learning in Diffusion Transformers

The paper investigates why Diffusion Transformers perform well when predicting clean data but poorly when predicting noise or velocity. It introduces the concept of *residual-stream burden*, explaining that noisy targets force the residual stream to carry noise-dependent variation through the network, limiting representation flexibility. Experiments show that spectral concentration of clean targets reduces this burden, and the authors propose Spatially Indexed Hyper-Connections (SiHC) to expand residual bandwidth, achieving state‑of‑the‑art FID on ImageNet.

By Tongtong Liang, Siqi Kou, Ziqiao Xi, Esha Singh, Kun Zhou, Zhijie Deng, Alexander Cloninger, Yu-Xiang Wang, Rahul Parhi
arXiv Computer Vision
2d ago

We Have Been Interpreting Diffusion Transformer Backbone Behaviors Wrong

The paper revisits the interpretation of depth profiles in Diffusion Transformer backbones, showing that the commonly observed inverted‑U curve reflects the influence of the prediction target (e.g., ε, u, x0) rather than a simple shift from coarse to fine semantic granularity. It argues that the semantically meaningful signal is merely an intermediate by‑product of predicting the target, and that different training setups—particularly the choice of prediction target—predictably alter the curve’s shape. The authors demonstrate how this new understanding can guide the optimal placement of REPA modules and provide code for further exploration.

By Benyuan Meng, Longtao Huang, Yang Liu, Liang Lin
arXiv AI
Jul 8

Few Channels Draw The Whole Picture: Revealing Massive Activations in Diffusion Transformers

arXiv:2605. 13974v2 Announce Type: replace-cross Abstract: Diffusion Transformers (DiTs) and related flow-based architectures are now among the strongest text-to-image generators, yet the internal mechanisms through which prompts shape image semantics remain poorly understood.

By Evelyn Turri, Davide Bucciarelli, Sara Sarto, Lorenzo Baraldi, Marcella Cornia
arXiv Computer Vision
Oct 22

How Do DiTs Denoise? An Aggregator-Predictor View of Attention and MLPs

The paper investigates how diffusion transformers (DiTs) denoise images by framing them as aggregator–predictor models that use context aggregation and patch prediction. It shows that for Gaussian Markov random field priors, a global Bayes denoiser can be approximated with a limited context, and that patchwise linear denoisers recover empirical local denoisers when aggregation is informative. Experiments confirm that DiTs trained on real images exhibit noise‑dependent denoising contexts and that replacing DiT MLPs with shared‑memory patch predictors yields competitive performance, while cross‑dataset component transplantation supports the proposed functional roles of attention and MLPs.

By Gyeonghun Kang, William Xingxu Chen, Xiang Cheng
Hugging Face Trending Papers
Aug 4

DiverseDiT++: Quantifying, Analyzing, and Promoting Representation Diversity in Diffusion Transformers

Recent advances in Diffusion Transformers (DiTs) have enabled remarkable progress in visual synthesis, benefiting from their superior scalability. To facilitate DiTs' capability of capturing meaningful internal representations, recent works such as REPA incorporate external pretrained encoders for representation alignment.

arXiv Machine Learning
6d ago

No Channels Left Behind: Understanding Diffusion Acceleration through Residual Gates

The paper investigates how diffusion transformer acceleration methods such as REPA and dispersive regularization affect the AdaLN‑Zero residual gate α, which controls conditioned updates in the residual stream. It finds that these methods reorganize α, making accelerated models more sensitive to its perturbations and aligning gate geometry with semantic class relationships. Introducing a normalized participation ratio (nPR) to measure gate channel organization, the authors show that broader gate participation correlates with higher generation quality and propose a teacher‑free radial objective that encourages this broader participation, improving FID on ImageNet.

By Junha Park, Jaemyung Yu, Jaehui Hwang, Jong-Seok Lee, Dongyoon Han