http://www.silentpcreview.com has been a great resource in my pursuit of quieter computing (sadly not updated as often as it used to be). I think I currently have 7 or 8 fans, all high-quality and large, and all spinning as slowly as possible. I can't hear anything, and it's wonderful.

You could try using a third party keyboard with a mac. I run an iMac with a mechanical keyboard, and the only thing I can hear is myself type :).

I meant the keyboard thing in general with regards to their apparent engineering direction. My current hackintosh does have a very loud keyboard otherwise :)

I use a Microsoft Natural Keyboard on my MacBook Pro, but then I'm typically at my desk.

Other than the common correlation with electricity usage and possible environmental benefits, I have trouble sharing the concern for the loudness of a powerful PC. Unless room space is very limited, I always just kept my PCs far enough away from my desk that the sound of fans became little more than regular ambient noise, not very noticeable against the fans or air conditioning I already had.

Granted, I never had any insanely beastly machines, generally just sub-$1500 gaming rigs. The only sounds that I ever even noticed were shorter irregular ones, like spinning disks. Perhaps the problem is simply more noticeable to other people, especially those with more powerful and thus louder machines, or people with smaller spaces who have their machines much closer, like on their desk or around their feet.

I care about ambient noise much more for other applications, like laptops or home theater PCs. For both of those, I have a strong preference for fanless models if at all possible.

The trash can Mac Pro seemed to be designed to sit on a desk, so quietness makes sense, although I don’t understand what’s so important about having very powerful machines on your desk. For machines like iMacs, the problem of placement is obviously unavoidable, but I struggle to understand why that form factor is desirable for a very powerful machine.

These days it is actually pretty easy to casually use liquid cooling for CPU and GPU fans which ends up being significantly quieter.

I have routinely been building nearly silent 99% maxed out gaming/vr rigs with integrated off the shelf liquid cooling units with no tubing or scary liquid interactions needed.

> Until the Mac Pro I hadn't considered that a modern, high power computer could also be dead silent.

You've never seen the rig of a competent PC modder before that? "Dead silent computers" were pretty much invented by those people.

Apropos, here these old Powermacs still fetch a nice price, because their cases are valued by modders for ATX conversions.

No, as I said I didn't imagine it possible from what I was used to, so I never spent the effort to look it up. I thought the difference would be between loud and very loud.

My G5 got really noisy when the fans would “fade in” while running a build in Xcode.