I have been battling a ComfyUI slowness issue for the last week and have narrowed it down to the LoRA Stacker node. When I have the Lora Stacker in my workflow, there is always a 6-7 second delay before image generation starts. During this time, there is no green box around any node indicating activity and the terminal just says "got prompt". After this delay, the progress indicator starts on the terminal and the workflow goes quick as it used to. I can't pin-point exactly when this became an issue, but it's most likely around 2024-08-15 when ComfyUI had their major update.

I have tested by keeping the lora stacker and replacing everythnig else (since I have a bunch of the Efficiency nodes in my workflow) and the delay happens whether or not there are any LoRA's listed in the stacker. It also doesn't matter if it's empty with multiple slots or just 1.

Lastly, I tried with ComfyRoll's stacker node and there is no delay when using it.

Let me know if there is any other info you need if you aren't able to reproduce. Thanks!