Got an older Dell Dimension 8200 [please see pic: front, back, inside]. Fan noise is inherent in all these Dell systems and it's mainly because it's a temp controlled fan [through a fan sensor not the BIOS] and it increases and decreases with the temp and the noise is simply the fan speeding up and vibrating the case. It's not as bad as some of the youtube vids where some sound like vacuum cleaners but it's bad enough that I want to fix it. The case fan is part of a plastic shroud that simply clips onto the metal casing and that's the problem...no way to add a rubber gasket like I did with the power supply. I've also done everything else I could to quiet the vibration...rubber feet, different fans, acoustic insulation. There's also two video cards in there, one with a heat sink and one with its own fan. I've narrowed the noise down to just the case fan and the vibration carried through the case when the fan speed increases after running all day. Okay that's the background. I love this PC...super fast and got too much $$$ into it to just dump it. One solution is to get a slower constant RPM fan, but my concern is heat buildup so now I'm wondering what could happen if I just leave the case cracked open...just about an inch? This case does not allow for completely removing an entire side...it simply hinges open. I've been running it all day at the bottom of my desk on it's shelf with the case cracked open and I can barely hear the fan. I've read pros and cons, from dust collection and just being unsafe to a more important concern which is that pc cases are designed with airflow in mind and hence...the case should be closed. The last con doesn't make sense to me though because this pc is really warm inside when I completely open it and, after about a minute of being open, it cools down and the fan slows down. Seems to me the case SHOULD be open. Sorry for the long post, but I wanted to explain everything in detail. Thanks all in advance for your input.