I've tried using Flash CC - I've used Flash CS4+ and had no problems whatsoever - and I noticed there was a terrible lag between my movement and the responsiveness of Flash.
I use mainly lines, and in previous Flash versions, the lines were instantly updated towards the location I was drawing them to. In Flash CC, there's a bit of a framerate issue(?) where the line takes a second before going where my mouse is.
I assume this is an issue with Live Previews, because every single dragging operation lags on Flash CC. Drawing a square, drawing a line, anything related to pressing and moving.
Is there any way to fix this? Is this a known issue? Is there any way to disable Live Previews - if that's really the case? My computer can certainly handle these things and I'm not sure why following my cursor is so hard.