February 22, 2018

Your PC has Many Fans

Filed under: Main — Tags: , — admin @ 12:01 am

The last quiet computer I owned was my TRS-80 Model 4P. Since then, all my PCs make noise — and not just from the speakers. Modern computers have fans to help keep them cool. A typical PC can have up to four of them or more.

Fans make noise, but they aren’t terrifyingly loud. In fact, the only time I notice the computer’s fans are when it’s doing something heavy-duty, like playing a graphics-intensive game. Then I hear all the fans revving up and blasting hot air out the PC’s rear.

For the first IBM PC, the fan dwelled in the power supply. It’s function was to keep the power supply cool, but it also helped circulate air inside the case.

As processors became more powerful, they grew hats in the form of tiny fans. Ditto for the display adapter, which has its own processor and little fan as well.

Finally, an exhaust fan is found at the back of many PC cases, which acts as a second cooling fan for the case in addition to the power supply fan.

Figure 1 illustrates where fans are typically located inside a PC’s case.

Figure 1. Where to find fans inside a typical PC.

The point of all the air blowing around is to keep the components cool. PC temperature specs vary. Most of the data you’ll find is on the processor, or CPU, which enjoys temperatures between 50° and 60° Celsius, or 122° to 140° Fahrenheit. Similar temperatures specs exist for the GPU, or Graphics Processing Unit, on a display adapter. The operating system monitors the temperature and can adjust fan speed to cool down a hot PC. And you can obtain utilities that monitor the temperature as well. In fact, some BIOS (more properly, UEFI) programs display temperature data.

While the processor, and the rest of the case can get hot, for the PC itself try to keep the room temperature between 10°C/50°F and 28°C/82°F. Anything colder or hotter and the computer may error. In fact, I remember computing a long time ago in my non-air conditioned apartment when it got too hot and the computer just turned itself off. Fortunately, nothing was damaged. Still, I hope that you understand and appreciate the many fans in your PC, and the job they do keeping it cool.


  1. A friend of mine built what thought was going to be a ‘quiet’ PC, No case fan, solid state hard drive & a fan less PSU. I did say when he told me of his plan ‘it’ll get very hot very quick’. Surfice to say all noise gains had to be undone as it ran some where between toastie hot to surface of the sun!

    Comment by glennp — February 22, 2018 @ 2:06 pm

  2. Was your friend Steve Jobs? 😀

    Supposedly, Jobs hated the noise computers made. The original Mac had no fan. The G3 “cube” Mac was a disaster because it lacked a fan, relying on convection to cool the box. Didn’t work.

    You’ve probably seen those images people post of their gaming PC setups, with all the liquid cooling and fans? It’s pretty cool. [sic]

    Comment by admin — February 22, 2018 @ 2:24 pm

  3. Yup, don’t really trust water cooling rigs, I have seen too many electronics damaged by water! funny thing is you see one after two or three years with all green stuff in it due to them using tap water rather than distilled.

    Comment by glennp — February 24, 2018 @ 8:33 am

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