Silent PC Review ( http://www.silentpcreview.com ) occasionally reviews complete systems. Last year they measured an i7 machine from Puget Systems at 11dB in their anechoic room ( http://www.silentpcreview.com/Puget_Serenity_Pro ) which is the best I've seen for an off-the-shelf PC.

I haven't used a Puget machine myself, but I've relied on Silent PC Review's component recommendations for nearly a decade, and never been disappointed.

I have seen full size ATX cases from Silverstone with passive cooling, where the entire case is machine out of aluminum and acts like an enormous heat sync. Have yet to find a good fanless power supply. The new Mac Pro supposed to be only 12DB. It's hard to beat that, most rooms have ambient noise of at least 18db.

> The new Mac Pro supposed to be only 12DB.

Until the dust hits it...

Solution: clean it once in a while :)

>Solution: clean it once in a while :)

Teach me oh great one. Honestly I've never managed to clean a fan. You can brush off the obvious dust but the noise comes from dust getting into the fan itself.

Spray it with compressed air inside and out. You can get into the slit between the fan housing and the motor and blow it out there as well. Most fans start making noise due to bearing failure / wobble, not the dust. I have a small home server with 4 fans. After almost 10 years now 3 out of the 4 fans are as quite as they were on day one, the 4th has developed a bearing issue and needs to be swapped out eventually. I am assuming that Apple will use hire quality fans then the $3 crap fans I am using.

>Most fans start making noise due to bearing failure / wobble, not the dust.

That exactly is the issue. They don't just mysteriously develop bearing failure / wobble...they do so because dust gets into the bearings. And that exactly is my point...no amount of compressed air can fix dust in the ball bearing grease. I just end up replacing all the fans after a few years...

Seasonic seems to have a pretty good fanless power supply.

There's some complete 'mini' systems that achieve this, presumably by pushing the the transformer out of the computer and into a wall-wart or similar: http://www.damnsmalllinux.org/store/Mini_ITX_Systems/533MHz_... http://www.amazon.com/Intel-D2500-Fanless-Mini-ITX-D2500CCE/...

Buying these as stand-alone components seems to be more of a challenge.

My MacBook Air (2012) is completely silent most of time (except viewing videos in Flash or Silverlight). Given is silent, I can actually hear the power supply of my monitor buzzing! (actually it's very quiet buzzing) - be careful what you wish for I guess.

but the video is so loud!

Yeah I know it's awful, if my Celeron 450Mhz could play DVDs at no effort, I don't know why this can't play videos on 5-10% CPU and not spin up the fan.

Most video encoding is mp4-type now (rather than the mp2-type used by dvds). Mp4 is typically a lot more processor intensive.

Any even vaguely modern laptop offloads mpeg 4 part 10 decoding onto a decoder chip or the GPU.

The older Mac laptops had (SMCUtil?) a utility to change the threshold for the fan - I know lots of Wintel systems have this in BIOS/EFI.

I have one, from http://www.quietpc.com/

It's completely silent, you can only tell that it's on by looking at LEDs.

Mac mini has fans but is basically silent.

things with fans are not silent enough - the mac pro seemed ok but now it seems too noisy

I guess that's what I get for living in the city...

my silent PC solution from 2008. Still the best value for money if architecture of your house supports it :) http://solnyshok.blogspot.com/2008/03/my-silent-pc-solution....

https://store.tinygreenpc.com/tiny-green-pcs/intense-pc.html Very silent fanless pc. I have one and I am glad.

If an i3 is fast enough for you, and you don't need high end graphics, you might want to consider an Intel "Next unit of computing" system... You'll need to get laptop components for it though. I've considered it, but not that into quiet, and want a bit more power.

http://www.newegg.com/Product/Product.aspx?Item=N82E16856102...

There are passive coolers for i7s out there. You can even find passively cooled GPUs and PSUs. It's pretty cheap to build a silent pc.

It's tricky getting a passive GPU to actually work, mine has a tendency to overheat and halt the system rather than throttle down under load. It required a fair bit of tweaking to case fans and driver underclock settings to get it stable.

Those passive coolers generally still rely on some airflow. With no case fans at all, I'm told they won't be able to hold up under any decent load.

Intel NUCs [1] are well engineered and extremely quiet.

[1] http://www.intel.com/content/www/us/en/nuc/nuc-kit-d54250wyk...

In the Netherlands there is https://ikbenstilcomputers.nl selling high-end fanless computers.