I just reformatted and reinstalled windows on my computer and I'm having this problem with dragging windows.
I know I can turn it off with "Show Windows Content While Dragging" but it's never done this before and that's really annoying to not have checked.
I have a Radeon HD 7750 and the newest drivers for it, installed completely fine, games run perfect and everything, but dragging windows is INCREDIBLY laggy, ALWAYS, but only when I drag them over other windows, they don't bleed on the desktop.
I'd been having this problem yesterday and today, so I'm surprised I figured out the solution only a few minutes after caving and asking here. I saw I didn't have windows aero on, turning it back on seemed to fix this. Stinkin' windows basic being LESS responsive.
But I guess it's good help for anyone googling similar problems.