NOISE.
When powered on, the fans shoot up to their maximum RPM for a second or so, then slow down. Depending on what you're doing the fan noise is anything from the level of relatively benign white noise to a constant or fluctuating jet engine like drone. Scanning for malware, playing a graphics-intensive game, defragmenting the hard drive, anything with lots of CPU activity prompts the Vostro 200's fans to go full speed.
I found a simple solution to this dilemma. Inside the case there are two 80mm fans for cooling the CPU. One is mounted directly atop the CPU heatsink, and the other is mounted vertically in a bracket along the right-hand side of the computer to push air out ventilation holes in the case.
I had a nice, quiet, 120mm NZXT "performance" fan lying around and decided to use it instead of the two 80mm turbofans that came with the system.
The CPU fan atop the heatsink is clipped on with several plastic clips, I simply removed each of these with pliers and discarded them since they'd just be in the way of the wider 120mm fan. The exhaust fan alongside is screwed to the case, so I removed it likewise and discarded it.
I then removed the vast amounts of dust and dog hair that had accumulated beneath the fan. As the case is lying horizontal to the desk, I decided to loop some narrow zip ties through the fan's screw holes and through holes in the rear grille of the case. I secured the ties with enough tension to keep the fan hovering just above the plastic and metal of the heatsink assembly.
It's a mystery why Dell chose seemingly the loudest fans possible for this computer. Or, perhaps it isn't so mysterious, perhaps loudness happens to be an unfortunate side effect of cheap hardware. Or, perhaps they wanted to make it seem especially sleek and high tech by having it mimic a 747 taking off.
Regardless, now the new 120mm fan runs at a quiet, constant speed, and keeps CPU temperatures well within normal limits, with no fear of liftoff.
