Your biggest fan

When I got around to building a computer recently, I was surprised how much time I spent dealing with one little factor: cooling. Of the four or so hours it took to put the system together, I spent about half of it wiring up fans and heatsinks and making sure they worked.

And for good reason: modern computers run hot, even when they're just standing still. While idling, the little AMD Athlon 64 CPU in my new machine runs at between 30 and 36 degrees Celsius (86 to 96 degrees Fahrenheit) and blows its exhaust beneath my desk. And under load, it gets much hotter, turning into a very expensive foot warmer. This is why a lot of the engineering that goes into a powerful notebook or desktop revolves around keeping these machines from melting.

I can't help but think that spending all this time and money on cooling is a little ridiculous. Building my own machine, I not only dole out a lot of cash to get a powerful chip and a power supply to run it, but now I'm spending extra on electricity to generate heat I don't want, as well as to run fans to suck that heat out of the case. If I had a bunch of these machines in an office and had to deal with air conditioning, I'd be paying for this excess power twice: once to create it, and again to cool the office back to a habitable temperature.

And did I mention the noise? Cooling the standard way -- by blowing air over heatsinks -- means running fans, and even quiet fans make noise. To quieten my new PC, I invested in a nice, sound-insulated case -- but I wouldn't have forked out the money if the machine were quiet to begin with.

Check your fluids?
The first is to take cooling to the extreme: dump the VW Beetle-style air cooling, and go with a system that can extract more heat without making a racket. In other words, liquid-cool the thing -- just like a regular car.

Water cooling replaces the heatsink and fan traditionally attached to your CPU with a waterblock -- a plate to which you plumb a fluid line. You pump liquid through the block, where it picks up the CPU's heat, then to a radiator that cools down the water before it heads back to the CPU.

Obviously, a water-cooled system is more complex than a standard air-cooled model, which is why it's primarily the province of PC homebuilders and modifiers ('modders'), not to mention supercomputer manufacturers. But CPUs and graphics cards keep getting more powerful (i.e. hotter), so we're likely to see liquid cooling in mainstream systems too. In fact, the new dual-processor Apple Power Mac G5 has liquid cooling, while the Poweroid 1200 uses Zalman's fanless TNN 500A case. More mainstream liquid-cooled machines will follow.

Apple's dual-CPU Power Mac G5 and the Poweriod 1200 are liquid-cooled, which minimises fan noise.

There's even a step beyond this, which I don't think we'll get to with mainstream products: immersion cooling, in which the entire PC circuitry is suspended in a bath of dielectric cooling fluid.

Old tech is quiet tech
Here's the other way to kill the heat from desktops: just say no -- say no to fans; no to power you don't need; no to the whole death-spiral of power, heat, noise and expense. CNET (ZDNet's sister site) columnist Brian Cooley tells me he's been 'stuck at 1GHz' for a while now. His machines use older technology, and he's happy there. His CPUs don't have as many transistors or as high a density as the electronics in today's machines and, thus, run cooler -- without fans, without massive copper heatsinks and certainly without the Three Mile Island-style cooling towers I fear we're all going to end up with alongside our desks if things keep going the way they are now.

But Brian has simple needs. He's not a gamer, and his three-year-old technology runs Windows just fine, as well as handling all the audio editing he does in his job.

Me, I want it all: power and quiet. And I'm willing to put up with sweaty toes to get it.

Modern computers run hot, even when they're standing still, and a lot of the engineering in a powerful PC simply keeps it from melting. But do you really need to spend so much time and money on cooling?