While poking around in the attic over the weekend, I discovered an entire spare PC. It's a Shuttle SN45. I fired it up and discovered:

1. That it still works.
2. The reason why it was in the attic: it's incredibly loud.

So: are there any relatively cheap ways to cool this PC silently, or should I just get rid of it?

I tried making an earlier Shuttle quieter and found that it was pretty hard to do so.

The main culprit was the tiny high RPM fan inside the PSU. If your power requirements are reasonable then something like a PicoPSU could replace it. As for whether its worth spending that much is up to you...

Aha. Shuttle still supply the SilentX PSU replacement that fits this model. Whether it's worth the outlay, I don't know...

What's a good other forum to discuss this on?

I've found it's hard to silence a large roomy desktop case, let alone a tiny little box like that.

Yes, the PSU is a major culprit, but you'll also run into trouble quieting down the CPU cooling fan and the video card cooling fan.

I'd recommend just googling for products that are specifically designed to quiet down the Shuttle. SilenX is a good place to start.

I used to have a Shuttle (AMD XP 2000 era) in the living room as my MythTV frontend. I got it second hand as a customer-returned unit at Aria computers in Manchester. It came with the ordinary PSU so I did a little switcheroo at work where we had a Shuttle with a SilentX PSU that lived in a machine room, despite it being an Intel box the supplies swapped over without any issues.

It PXE booted so had no discs in it and had a passively cooled gfx card. Once the big fan had ramped down after boot it was really quiet, certainly not obtrusive.

I'd recommend the same, but it's not going to be difficult at all to replace the PSU fan. Actually, it's a whole heck of a lot easier than in a normal system!

Remember Tony, Shuttle's cooling method is to use heat pipes that go back and up to a heatsink on the back of the system, and have a fan blow the air over that (image below). It's really easy to remove/replace that fan (you don't have to touch the heatsink).

I'd definitely pick the PSU fan as the culprit. The PSU in my wife's Shuttle went bad a little faster than I would have hoped. And that's a tiny fan in there that's probably spinning pretty fast.

The Shuttle SN45G takes a standard-sized 1U rackmount PSU, so I swapped it out for a Seasonic SS-250SU. It's definitely quieter but, more importantly, the noise is also a different pitch, so it's not as annoying. I think the most important thing, though, is that it's temperature controlled.

According to "sensors", it's running at 38C, which I'm happy with.

Using a borrowed power meter, it's drawing 16W, as compared to the current server's 130W or so.

I'm going to look at swapping out the CPU fan the next time I have more than £4 worth of stuff to buy.

The only other things making any noise are the internal hard disk -- I might look at a CF/IDE adapter (unless anyone makes PATA SSD drives) -- and the video card fan (but passively-cooled AGP cards are kinda hard to find these days).

Currently, it's sitting on the floor (I removed the metal feet and replaced them with rubber ones), with a 1TB WD MyBook hanging out of the back.