By and large, it appears reasonably easy to put a fairly quiet PC together, using even cutting edge components to populate its interior. The secrets to this exercise are to limit the number of small fans you permit to operate in the interior, to select drives that make less rather than more noise and to choose a case that provides ample ventilation and cooling. However, it is also necessary to ensure that the path by which sound exits the PC is as long as possible when reaching its user’s ears.
We also have to believe that picking a passively-cooled graphics card is a key selection criterion, because VGA coolers are notorious for generating sound inside a PC, especially for fans of the so-called "squirrel cage" variety. Through experimentation and experience, we’ve come to believe that it’s better to rely on more big and slow fans in the case to provide reasonable air circulation and cooling, than it is to allow components with built-in fans to take up residence therein.
Certainly, those users who decide to install three or more disk drives into the CoolerMaster Cosmos case - which has plenty of room to accommodate them - should plan to install an additional 120 mm fan in the mounting space that the CoolerMaster so thoughtfully provides for that purpose. We’d also urge such users to go ahead and spend the $12 to $17 that they will have to spend for a 17 dBA rated Nexus case fan for that spot, fluorescent orange coloring notwithstanding. Indeed, it might be a good idea to consider purchasing a fan controller and plugging all four of those five 120 mm fans into such a device so you can monitor internal temperatures and adjust fan speeds to the lowest levels that also keep your components acceptably cool (for the fifth fan, we recommend purchasing a fan rheostat of some kind, such as the FanMate unit bundled with many Zalman coolers, or similar products from Swiftech that cost about $12). With fan controllers from vendors such as Vantec Nexus ($20), Thermaltake ($45) and Ultra ($20), among many others - all of which offer four separate speed controls - this is an ideal way to limit fan noise for those seeking as much quiet as they can get into their PCs.
Likewise, the choice of power supply should emphasize efficiency (80-plus percent or better), large fans (90 mm is good, 120 mm better), and intelligent temperature-based fan controls. On the Seasonic, Corsair, Zalman and CoolerMaster PSUs we’ve come to know and love over the years, we’ve seldom seen PSU fan speeds in excess of 800 RPM. For 120 mm fans, this is a moderate speed that moves lots of air, yet generates little noise.
Finally, we can’t emphasize the importance of low power consumption for PC components enough to those who seek quiet as well as computing capability. 2. In researching this story, we observed that many of the most efficient power supplies work most efficiently at 50% of their rated power output. Thus, for example, Corsair claims that the VX450 power supply we used for this story operates at 85% efficiency at 225 Watts output. The Corsair 450-W PSU unit, for example, used 225-W, while the firm claims 85% efficiency for this power supply. Thus, if you can estimate your real peak load and buy a power supply that hits its efficiency peak at that load, you’ll minimize its cooling needs, extend its life and save money on power into the bargain. Luckily for us, we appear to have stayed a little below that level on both of our builds.