Normally the pointer is not effected by CPU usage. It is always smooth no matter what.
The problem is that it is not as butter smooth meaning your eyes do not detect any irregularity in the movement when you are using a high quality mouse (in my case Logitech G700). With high quality mouses, the mouse moves as if you were using an Amiga computer.
When CursorFX is running, your eyes detect irregularities in mouse movement. It no longer moves smooth as butter but your eyes detect micro stutters in its movement. It seems like the method CursorFx is using to display the cursor is not the right method for smooth movement since the mouse is always smooth when not using CursorFX. Even in games hat use custom animated big cursors.