Good airflow, provided by quality system fans, is like sweet, sweet love for your PC. But this isn't the noisy kind of love (steady!), it's as quiet as it comes. With a diameter of 120mm and a depth of 25mm, this fan is capable of gulping gallons of air into (or out of) your chassis.

Joyfully, it does this at a nearly silent volume, due in part to the fact that it runs at a rather stately 720RPM, pretty slow for a case fan, and also because it features sheathed bearings.

At seven nicker, it's one of the most effective, yet cheapest upgrades you can buy for your PC. But remember to check your chassis fittings first - 120mm fans don't fit all cases.