About a month ago, my computer froze up for no aparent reason, and wouldn’t get past POST (that is, wouldn’t show the BIOS screen). I’d had this problem before, on my old setup, so I did the same thing I had done before: taken out the CPU and cleaned the dust from around it. Now, I’d been planning on re-attaching the CPU cooling setup I’ve got, now that I had figured out the proper method for applying the thermal paste—the goo that conducts heat from the CPU itself to the heat sink on top (which the fan then blows through, taking away the heat)—so I didn’t hestitate to do it. As it turns out, some dust had worked itself under the CPU somehow, shorting out one of the pins on the CPU (which was what was causing the computer not to boot), so a quick spray of the canned air I had took care of it. However, thermal paste is pretty messy, and not something I’d want to re-apply again, so I needed to get the dust issue fixed relatively soon, before I had to do that kind of thing again. Now, since my CPU runs so hot (P4 w/ hyperthreading, and I’m compiling stuff pretty regularly) I can’t get away with closing the case. This is annoying, as the 7 fans I have in the case (2 on the HDD, 2 case fans, 1 CPU fan, and 2 power supply fans) are pretty loud when the case is open.
So, attempting to solve the noise, dust, and cooling problems all at once, I hit upon a solution: drill a hole in the side of the case, and run some ducting from the edge down to the CPU (about 4 inches away). Since I was going to Lowes to buy a furnace filter anyways, I figured I’d knock all that out of the way tonight by getting the supplies I’d need. Specifically, a metal drill bit larger than 83mm, an extra furnace filter I could cut up, and some flexible ductwork I could run from the case panel to the CPU. I ended up buying everything (about $30, though $20 of it was the drill-bit), and setting it up tonight. End result: after closing the case up, the CPU temperature is now the same when the case is closed as it was when the case was open, and it’s sucking filtered air over the CPU’s heatsink. That means that pulling air from the outside through a furnace filter translates into about a 5°C drop in temperature from using the air already in the case. Not bad if I do say so myself :-).