I have a 20G 360 and don't really care if I can only copy one game at a time... I'm used to sticking to a game and right now nothing has me more hooked then Gears :)
I currently have Gears, GTA4, Perfect Dark and Mass Effect, I've only noticed this in Mass Effect. Loads times at the end or beginning of a stage is expected but it's annoying when it occurs while you're firing a weapon.







