fabric 6/fabric 7 Text effect: Gradient fill + gradient border + shadow result in slow rendering.

[J-env]

When there are many text effects (gradient fill, gradient border, shadow) on the canvas, and when moving, scaling, or rotating layers, the canvas rendering speed slows down, and the objects become sluggish in following the mouse.

[asturur]

Yes in that case you should use caching.
Just following the mouse should be a free operation if you are dragging a cached object.
Shadow is a costly operation you will have to pay even if you have caching on.

Can you make an example online somewhere so we see how much slow this is it?
You didn't attach a flame graph or an example, nor an fps stats.