Phones Are As Powerful As PCs, So Why Don't They Need Fans?

howtogeek.com:

Mobile phones grow more powerful every year. A premium phone is far more powerful than a midrange PC and even has stronger graphics processing than an ultrabook with Intel-integrated graphics. Yet despite all that power, have you ever noticed how your phone lacks a fan? Why is that?

Moving Parts Need More Space and Can Break

Phone makers have spent years making their devices as thin as possible, and these handsets would not be just a few millimeters thick if they had to account for fans. Fans are bulky, and they need space to move. They also break pretty quickly if put under abuse.

What qualifies as abuse? Well, pretty much anything you do with a phone. Tossing it on the couch. Strapping it to your wrist as you go for a jog. Knocking it out of bed and onto the floor, case or no case. Everything else in your phone may survive just fine, but your fan would start rattling. It may still do its job, just noisily. Or it may become bad at its job, leading everything else to gradually overheat and fail.

Fans Don't Like Small Dark Spaces

Devices that depend on fans for cooling generally don’t like to be kept in tight, cramped quarters. Rest your laptop on a pillow while doing intense work and see how quickly things start to bog down.

Now imagine carrying a smaller version of your laptop in your pocket. If it didn’t get hot enough to immediately attract your attention, it would probably just shut down at some point. Battery life will surely take a hit. A purse is better, but probably not by much. After all, a laptop gets along well-enough with a messenger bag only because it’s either off or very nearly so.

​Mobile CPUs Use Less Power and Create Less Heat

When trying to determine how energy efficient your CPU is, there’s one key term you’re looking for: Thermal Design Power. TDP is usually listed in watts and shows the maximum amount of heat the CPU is designed to generate when running under a full load. This doesn't tell you how much energy your device is pulling every