After putting together a Linux machine based on the Intel Celeron E3200 (whose performance exceeded my expectations), I began to read a bit more about CPU fans that are controlled by pulse-width modulation (PWM). A lot of reviewers of the E3200 panned the stock Intel fan, with many saying that it's too loud. After searching a bit, I installed the
lm_sensors package and began to monitor the temperatures and fan speeds on the system. I noted that the PWM seemed to be working nicely, adjusting up and down according to the temperature of the CPU.
Then I learned about heatpipes and wondered if I could make the system somewhat quieter with a better fan than the stock Intel fan. I stumbled upon the Cooler Master Vortex 752 CPU fan, pictured above, at Fry's, which had a markdown on these fans. So I bought one and replaced the stock fan with it. But curiously, the new fan was running at full speed all the time (about 2450 rpm) and producing not less noise than the old fan. I was perplexed about why PWM wasn't working in this case.
Today I found out that there are utilities in the lm_sensors package that allows one to tinker with fan speed settings. After running pwmconfig, and then fancontrol, I was able to lower the speed of the new fan (to around 800 at idle) without affecting the temperature of the CPU, and the system got much quieter. So I can highly recommend the fan at least for building quiet systems.
