There's an art and craft to building fanless computers that can do fancy things (like play games), but the one Tim made is housed in the attractive Streacom DB4 and makes no noise at all. Zero decibels. Tim had to research motherboard clearances to the fraction of a millimeter to make sure he picked the right one to work with its heatpipe kit.
This computer makes no noise when it starts up. It makes no noise when it shuts down. It makes no noise when it idles. It makes no noise when it’s under heavy load. It makes no noise when it’s reading or writing data. It can’t be heard in a regular room during the day. It can’t be heard in a completely quiet house in the middle of the night. It can’t be heard from 1m away. It can’t be heard from 1cm away. It can’t be heard — period. It’s taken nearly 30 years to reach this point, but I’ve finally arrived. The journey is over and it feels great.
The full-size Streacom DB4 is $300 at this site; a miniature version is available on Amazon for some obscene sum but you won't be building anything with much grunt in it.