Hardware Reference
In-Depth Information
system BIOS setup programs can display the fan performance and report it to a system
monitoring program. Because some processors—particularly older Athlon processors—can be
destroyed in a few moments by a malfunctioning processor heatsink fan, this feature can help
prevent a disaster inside your system.
If you need to purchase an active heatsink, be aware that some on the market are of poor quality. The
bad ones have fan motors that use sleeve bearings, which freeze up after a short life. I recommend
only fans with ball-bearing motors, which last about 10 times longer than the sleeve-bearing types. Of
course, they cost more—but only about twice as much, so you'll save money in the long run.
Newer fans include four-wire power connectors, which feature the standard power, ground, and tach
wires found in three-wire fans, but they also add a fourth wire for fan-speed control. These are
known as PWM (Pulse Width Modulation) fans because they use pulse width modulation signals from
the motherboard to control their speed more precisely and with more variations in speed. Standard
three-wire fans have internal thermal resistors (thermistors) that control fan speed, and these normally
offer only two-speed operation. With the PWM setup, the motherboard can monitor system and
processor temperatures and variably control the fan speed to maintain the desired temperatures.
Heatsinks designed for LGA775, LGA1156, LGA1366, LGA1155, or LGA2011 sockets usually
include plastic retainer clips that snap into holes in the motherboard. To install this type of heatsink,
you merely align the tops of the clips such that the arrows are rotated all the way to the left (opposite
the direction of the arrow) and then press the tops down until the bottom parts click and lock into the
holes in the motherboard. To remove the heatsink, you insert a flat blade screwdriver into the slot
under the arrows and then rotate the tops in the direction of the arrows. As you rotate each clip, it
will pop out of the motherboard.
Figure 3.53
shows an active heatsink for Socket LGA1155
processors, featuring these snap-in retainers.
