Hardware Reference
In-Depth Information
Intel sockets
The oldest of the current Intel sockets is the obsolescent
Socket LGA
775
, also known as
Socket T
. Socket LGA 775 processors and mother-
boards are still widely available, and are likely to remain so through
at least 2011 and into 2012. It's not necessarily a bad idea to build a
new system around an obsolescent socket—prices on older gear are
often excellent—as long as you're aware that it may be difficult or
impossible to find a replacement motherboard or processor two or
three years down the road. At worst, you may need to replace both
the motherboard and the processor if one or the other fails. Socket
LGA 775 motherboards accept dual-core Pentium processors, single-
and dual-core Celeron processors, and Core 2 Duo and Core 2 Quad
processors.
Intel's current entry-level/mainstream socket is
LGA 1156
, also known
as
Socket H
. With this socket, Intel moved functions formerly per-
formed by the separate northbridge section of the chipset onto the
processor chip itself, which accounts for the need for almost 400 more
pins than LGA 775. The high-speed Direct Media Interface (DMI) link
formerly used to link the northbridge and southbridge sections of the
chipset is now implemented within the processor package, as are the
QuickPath Interconnect (QPI) formerly used to connect the processor
to the I/O hub (southbridge), a PCI Express 2.0 x16 link for commu-
nication with a graphics adapter, and a dual-channel DDR3 memory
controller. In effect, LGA 1156 moves all of the high-bandwidth func-
tions formerly performed by a separate northbridge onto the proces-
sor itself and leaves only the former southbridge chipset functions on
the separate southbridge chip, now called the
Platform Controller Hub
(PCH). Socket LGA 1156 motherboards accept Core i3, Core i5, and
Core i7 processors. LGA 1156 processors and motherboards are likely
to remain Intel's mainstream desktop solution for the next few years.
Intel's current performance socket is
Socket LGA 1366
, also known
as
Socket B
. Like LGA 1156, LGA 1366 uses an external southbridge
chip for USB and other communications functions, and incorporates
a DDR3 memory controller on the processor (triple-channel DDR3, in
this case). The major difference between LGA 1156 and LGA 1366 is
that the latter moves PCI Express off the processor chip, using a QPI
link to communicate with a separate partial northbridge chip that sup-
ports video and other PCI Express communications. Socket LGA 1366
motherboards currently accept only Core i7 and Xeon (workstation/
server) processors. LGA 1366 processors and motherboards are likely
to remain Intel's performance desktop solution for the next few years.
AMD sockets
Like Intel, AMD has three current processor sockets, but in AMD's case
the three sockets are actually just very minor variations of one socket.
In fact, the 940-pin Sockets AM2 and AM2+ and the 941-pin Socket
