Paintstormstudio.com

Hi,

It seems the application itself is hogging all the CPU on a 27" 4k. I have a macbook pro . WIthout using the external display The GPU usage is normal... however when I plug in the external display... performance-wise it's not the best

https://i.imgur.com/92ke5vw.png

Paintstorm uses CPU cores only for some actions like image or layer resize. In drawing it's not expedient.
I think your brush that looks large on 1920(for example) display looks tiny on 4K display and you just increase the size to something like 800px and this large brush already slow - need to increase spacing.