I just bought the paid version and am noticing the same exact problem. When I'm simply drawing a line in Draw Persona, the line lags behind the pen AND the fan in my MacBook Pro starts to run at full speed like when I'm playing a graphics-intensive video game.
I'm just drawing a line... no fill or anything that would strain the CPU, right?
Also, in preferences what are people setting their preferences for RAM usage at?
My MacBook: 2.4 GHz Intel Core i5, 4 GB memory, 1600 MHz
Drawing with a Wacom Intuos CTH-680 Pen & Touch
Thanks for any suggestions!