These people aren't buying a vapochill though, they are building their own, if you know how to do it, it can cost as little as $100 to make a phase change setup
I don't know all the details of phase change, I believe it carries the hot air away from the CPU, changes it into water, cools it down somehow to extremely freezing temperatures, somewhere along the line changes it back into a gas, and then sends the uber cool air back to the CPU
It uses gas like propane, which I don't know if you've ever felt propane leaking out of a tank in air form, but it's mighty cold then much less when it's highly compressed into a liquid form.
(mind you I don't know all the specifics) but it does not draw heat away from the CPU more than it does simply bombard it with extreme cold. This is truly active cooling. The propane gas is basically converted from high compressed liquid to gas and back again, this is what they mean by 'phase change' of course going from liquid to gas. The propane as I said is what is really really cold. You of course can't feel the cold coming out through your propane grill because that's not pressurized, take it out off the grill and release the valve so that it all rushes out at once, and you'll be able to tell it's cold
Also gaara , honestly the computer parts cost way more than that phase change did because as I said, he built it lol which can be very cheap but you also have to know quite a bit