Hardware Reference
In-Depth Information
Figure 3.8
Pentium and Pentium Pro processor sockets.
When the Socket 1 specification was created, manufacturers realized that if users were
going to upgrade processors, they had to make the process easier. The socket manufactur-
ers found that 100 lbs. of insertion force is required to install a chip in a standard 169-pin
Socket 1 motherboard. With this much force involved, you easily could damage either the
chip or the socket during removal or reinstallation. Because of this, some motherboard
manufacturers began using low insertion force (LIF) sockets, which required a smaller 60
lbs. of insertion force for a 169-pin chip. Pressing down on the motherboard with 60-100
lbs. of force can crack the board if it is not supported properly. A special tool is also re-
quired to remove a chip from one of these sockets. As you can imagine, even the LIF was
relative, and a better solution was needed if the average person was ever going to replace
his CPU.
Manufacturers began using ZIF sockets in Socket 1 designs, and all processor sockets
from Socket 2 and higher have been of the ZIF design. ZIF is required for all the higher-
densitysocketsbecausetheinsertionforcewouldsimplybetoogreatotherwise.ZIFsock-
ets almost eliminate the risk involved in installing or removing a processor because no
insertion force is necessary to install the chip and no tool is needed to extract one. Most
ZIF sockets are handle-actuated: You lift the handle, drop the chip into the socket, and
then close the handle. This design makes installing or removing a processor easy.
The following sections take a closer look at those socket designs you are likely to en-
counter in active PCs.
