Hardware Reference
In-Depth Information
Cooling a high-wattage processor such as the Pentium 4 requires a large active heatsink.
These heavy (sometimes more than 1 lb.) heatsinks can damage a CPU or destroy a
motherboard when subjected to vibration or shock, especially during shipping. To solve
this problem with Pentium 4 motherboards, various methods have been used to secure the
heatsink in the system. Intel's specifications for Socket 423 added four standoffs to the
ATX chassis design flanking the Socket 423 to support the heatsink retention brackets.
These standoffs enabled the chassis to support the weight of the heatsink instead of de-
pendingonthemotherboard,aswitholderdesigns.Vendorsalsousedothermeanstorein-
forcetheCPUlocationwithoutrequiringadirectchassisattachment.Forexample,Asus's
P4T motherboard was supplied with a metal reinforcing plate to enable off-the-shelf ATX
cases to work with the motherboard.
Socket 478 systems do not require special standoffs or reinforcement plates; instead, they
use a scheme in which the CPU heatsink attaches directly to the motherboard rather than
totheCPUsocketorchassis.YoucaninstallmotherboardswithSocket478intoanyATX
chassis; no special standoffs are required.
Socket T (LGA775) systems use a four-side frame locking mechanism that holds the pro-
cessor in place. The heatsink is positioned over the processor,and locking pins attach it to
the motherboard. Later LGA sockets use a similar design.
BecausethePentium4processorfamilyhasbeenmanufactured inthreesockettypeswith
awidevariationinclockspeedandpowerdissipation,it'sessentialthatyouchooseaheat-
sink made specifically for the processor form factor and speed you own.
Intel Pentium D and Pentium Extreme Edition
Intel introduced its first dual-core processors, the Pentium Extreme Edition and Pentium
D, in May 2005. Although these processors used the code name Smithfield before their
introductions, they are based on the Pentium 4 Prescott core. In fact, to bring dual-core
processors to market as quickly as possible, Intel used two Prescott cores in each Pentium
D or Pentium Extreme Edition processor. Each core communicates with the other via th
MCH (North Bridge) chip on the motherboard (see
Figure 3.30
)
.
Figure 3.30
The Pentium D and Pentium Extreme Edition's processor cores communicate with each other
via the chipset's MCH (North Bridge) chip.
