I've made an Extension "Batched Hires"!

[aleksusklim]

Here is the repo: https://github.com/klimaleksus/stable-diffusion-webui-batched-hires

With this, you can set a separate Batch Size for the second pass of Hires.fix to be lower than your main batch size.

So that you will be able to use large batches on low-resolution pass, but small batches (even 1 to effectively disable batching) when upscaling that!

It will fit in your GPU easily by making several hires calls under the hood (which might break other extensions, of course)

Overall your resource usage will become more efficient when using Hires.fix, because now you can greatly increase your main batch size for lowres pass, utilizing all available VRAM no matter how large you are upscaling at the same time.

(Previously, when using big target upscale resolution in Hires.fix you most likely had to set your batch size to 1 since otherwise it could OOM on the second pass).

Works with SDXL, works with Tiled VAE (which I recommend to use!), works with ControlNet.

I did not test it with combinations of other extensions, but if you find it non-working with any actually useful extension – let me know by creating an Issue in the Batched Hires repo.

[aleksusklim]

Does anyone know, has AUTOMATIC1111 any future plans to separate the batch size of hires.fix officially?

Probably, that should be done not like my extension is doing it currently. Another variable should be introduced, and another callback for scripts.