Dual-fan CPU coolers have become more common because it is not possible anymore to increase the performance of single-fan coolers by simply making their heatsinks larger or putting more heat pipes into them. So, some manufacturers have begun to ship coolers with two fans and others provide for the installation of a second fan by designing the heatsink in an appropriate way. With one intake and one exhaust fan, an air cooler is going to lower the peak temperature of a CPU by 5 to 7°C at low speeds and by 2 to 4°C at high speeds compared to itself working with only one fan. That’s the general rule I can infer from our tests of such coolers as Thermaltake’s FrioOCK and Frio, Sunbeamtech Twister 120, Noctua NH-C14, Spire TherMax Eclipse II, and others. Today, two more products from Cooler Master and Thermaltake Technology will be added to this list.