[PSA] Stability.AI released official SDXL update -- CosXL

I had the chance to meet the SDXL authors in person and look at their poster.

Stability recently released an official SDXL update called CosXL.

Notes are based on listening to their discussions with others.

When SDXL was first released, some people pointed out that SDXL did not follow best practices such as (A) Using v-prediction. (B) Using ZeroSNR. (C) Using Cosine Schedule.
The consequence of these choices is that (A) Without using v-prediction it is hard to use ZeroSNR, as the model may struggle to train. (B) Without ZeroSNR, the model struggles to generate dark/bright images. (C) Without using Cosine Schedule, the model converges slower.
Dustin (SDXL first author) mentioned that while during the 0.9 to 1.0 beta period, they had a model with these features, at the time the model with fixes lost against the unfixed model on a variety of factors.
Recently, Stability AI released a finetune of SDXL with these features called CosXL (https://huggingface.co/stabilityai/cosxl/tree/main). Which has v-prediction/ZeroSNR/Cosine Schedule. As a consequence, the model should be able to generate bright/dark images much better, and should generate images with much higher quality when using fewer steps.

Given the recent news about Stability's situation, I think it is very nice that they at least released one last SDXL update.