It’s not a rare occurrence that performing a resource heavy task on your Android device (e.g. playing a game or multitasking heavily) results in the back of your device getting quite hot due to the heat being generated by the CPU. And without proper or adequate heat distribution, this heat will be most prominent at a certain area of your device’s rear. Strong heat is not the only downside of a hot CPU however, as it can also result in decreased performance due to throttling, less battery life, and a lower overall device longevity.
With this said, XDA Senior Member ottomanhero figured out a very clever way of remedying this issue on his LG Optimus 4X HD after noticing that playing games on this phone results in a certain part of the phone’s rear getting hot. He pinned this down to unequal distribution of heat behind the back cover, and decided to tape aluminum foil around the back to direct heat from the hot area to cooler areas.
After conducting tests with this homemade heat sink in place, ottomanhero found that he experienced much better and lower temperatures emitting from his device. There was also an issue with the device’s GPS signal being weakened as a result, but later resolved this with a new method. Ottomanhero has provided a picture that clearly shows this modification, and has also written a detailed tutorial teaching you how to do this yourself.