to be as light as possible; the form factor has to be built around the standard keyboard layout; users are very close, so noise must be kept to a minimum, and the case exterior temperature must be kept low enough to be used on a lap. Cooling generally uses forced air cooling but heat pipes and the use of the metal chassis or case as a passive heatsink are also common. Solutions to reduce heat include using lower power-consumption ARM or Intel Atom processors. Mobile devices Mobile devices usually have no discrete cooling systems, as mobile CPU and GPU chips are designed for maximum power efficiency due to the constraints of the device's battery. Some higher performance devices may include a heat spreader that aids in transferring heat to the external case of a phone or tablet. See also CPU power dissipation Thermal design power Thermal management of electronic devices and systems References External links CPU Cooler Rules of Thumb Submersion Cooling Patent Application DIY Submersion Cooling (Fish Tank + Mineral Oil) Gametrailers.com Forum - Videos [1]. [2], [3]. Central processing unit