Recently I've noticed my black friday n3ds warms up pretty fast, usually in under 20-30 minutes. I do not remember it always being like this and cools down while in sleep mode. Not sure if this is unusual since I've read about people saying their 3ds doesn't warm up for hours. I worry if I leave it on too long it'll over heat the system. It gets pretty uncomfortably warm. It warms on the bottom center (not on the right where the battery is) where the microsd is.