Description:
This workflow is very useful for those who, like me, run into memory shortage errors in ComfyUI with complex workflows.
This workflow is designed for graphics cards with low VRAM, as well as CPU‑based users, or users like me who have AMD GPUs.
You can generate the image in a simple workflow, and then in this workflow, you can both fine‑tune and upscale it using Ultimate SD Upscale without getting errors.

Which models is it suitable for?
You can use it with all SDXL, SD1.5, Illustrious, and Pony models.
Keep in mind that the model must have its own built‑in clip and vae.

CLIP Text Encode
In this section, enter the same positive and negative prompts you used to generate the original image.

Ultimate SD Upscale
Adjust the settings according to your needs and the model you used to generate the image. Just set the tile_height and tile_width between 512 and 1024 depending on your VRAM and RAM capacity to avoid memory errors.

Load Upscale Model
Use any model that suits your image, such as RealESRGAN (anime or realistic).