Water cooling. What is it with water cooling? When I say to someone "I water cool my PC", I get a puzzled look and a comment like "You're insane" or "That's stupid. You'll fry your computer". Yeah, that's the exact fucking reason I'm doing it. Because I want to kill the $1100 power machine I built myself with my own money. I don't see what's wrong with it anyway. Water is something like 5 times more efficient at absorbing heat (without heating itself up) than air is. Example: take a pound of water, a pound of iron and a pound of gold, (this bit's out of an encyclopedia) all at absolute zero. If all three were heated and absorbed the same amount of energy, the gold would melt at 1102ºc, and the water would be at -184ºc. When the iron melted at 1299ºc, the water would have reached 0ºc.
And all the heat gets dumped outside your case. Stick a massive Alpha sink on your CPU, video cards, hard drive, whatever. Hell, stick the fucking things all over the inside and outside of your case. Stick one on your monitor. Modem running warm? Put one there, too. You could put a heatsink the size of your head on your processor (and someone probably has a bigger one), and all the heat still gets dumped inside your case, making you resort to covering every available surface with fans to remove heat. And removing said heat from the sink is easier said than done. Huge fans spinning at a million billion RPM and pushing a trillion CFM seem popular, even though they sound like a 747 taking off.
I read on some hardware site a line like this: "for those of you that prefer cooling performance over quiet". Sorry, but my ideal machine isn't one I have to turn off when friends come over. Nor is it one that requires the TV to be turned up while it's running. And that's why water cooling is so good: It can be as silent as you want. All the noise it makes is from the pump (although you could use natural convection), and the fans. The fans aren't strictly necessary, but they are better than a passive radiator. And you can use whatever sort of fan you like: low noise, high noise, three pin, four pin, AC, DC, whatever. All the fan does in move cool air over the radiator to cool it down. You don't have to suck heat you could barbecue with off it (unless you're into peltier devices). I could just imagine grilling things on an air-cooled, overclocked P3.
It's dangerous? No more so than air cooling. RTFM, do everything exactly like it says, and nothing should go wrong. That funky Alpha sitting on your CPU weighs an absolute shitload, I'll bet. And I'll laugh like a fucking hyena when it snaps your CPU in half and breaks every add-on card on the way down. The water block, the most important part of the system (apart from maybe the water), weighs practically nothing. It's made out of a tiny amount of aluminium or copper, and it's pretty much well hollow anyway.
The price? Here's the bad bit. An Alpha sink, with fan, might cost you, say, $50. A full water kit, for example, the Senfu, might set you back two or three hundred. But here's where water cooling really starts to shine: you're paying an absolute boatload of cash for your cooler, and the manufacturers are nice enough (most of the time) to supply enough different mounting clips and plates (and screws and bolts) to let you attach the block to almost anything. Some of those more unindentifiable bits might even let you attach the damn thing to your head. Or your car. Or your dog. They want to make absolutely sure you can stick the block on anything you fucking well want, and you pay through the nose for it.
Another rant, written around mid 2000. Incidentally, about five months after I started using water cooling, the Senfu waterblock I was using decided to succumb to galvanic corrosion and developed a number of... holes. Didn't kill anything, but I ended up using an Alpha PAL6035 on my CPU instead. How ironic. The original version of this rant, with spelling, formatting, and extra paragraphs intact, can be found at http://epoch.iwarp.com/dotrant/2.html.
Incidentally, I did used to have a heatsink designed for a T0-3 transistor with a 40mm fan on my modem, because it used to get suspiciously warm in one spot. The HSF is gone now, though, because the modem now has my hub stacked on top of it.
Want to see the process for yourself? Of course you do! Tom's Hardware Guide has a step-by-step video showing you the setup of a water-cooled system:
Much kudos and props and whatnot to Orpheum for /msging me the URL. :)