Slots and Sockets

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There are two major ways that a CPU or processor can be installed on the motherboard: socket design and slot design. The socket design is square and is made for a Pin Grid Array (PGA) or Staggered Pin Grid Array (SPGA) chip package. The socket itself is made up of many tiny holes that correspond to pins on the bottom side of the CPU. This socket is known as a Zero Insertion Force (ZIF) socket. Socket design is also referred to as flat architecture (see Table 2.1).

Slot technology is implemented when a CPU that is already attached to an Integrated Circuit (IC) board is plugged into a slot on the motherboard. This slot is typically known as Slot 1. Slot technology is pretty much the standard today. There are variations of slot and socket technologies designed to support specific CPUs (see Table 2.2).

Note 

It is important that you pay close attention to the tables in this chapter. The A+ Core Hardware 2003 Objectives are sure to test your knowledge regarding the newer slots, sockets and CPUs. Know them well.

Table 2.1: Major Sockets, Slots, and the CPUs They Support

Socket or Slot	CPU
Socket 7	Pentium (75MHz), MMX, X86, Cyrix MLL, AMD K-5, K-6
Socket 8	Pentium Pro
Socket 370	Pentium III PGA, Celeron PGA
Socket 423	First-generation Pentium 4 (423-pin Willamette)
Socket 478	Second-generation Pentium 4 (478-pin Northwood) Celeron Family (478-pin Northwood)
Socket A	AMD Athlon PGA, AMD Duron, AND Athlon XP
Slot 1	Pentium II, Pentium III SEC, and Celeron SEP
Slot A	AMD Athlon SEC
Slot 2	Pentium II Xeon, Pentium III Xeon

Table 2.2: Details of Major Slots and Sockets

Socket 7	321 pinholes (19x19), SPGA ZIF socket
Socket 8	387 pinholes (24x26), MSPGA ZIF socket
Socket A	453 pinholes (19x19), SPGA ZIF socket
Slot 1	242 leads, SEC slot
Slot A	242 leads, SEC slot
Slot 2	330 leads, SEC slot
Socket 423	423 pinholes, PPGA
Socket 478	478 pinholes, PPGA FC-PGA2

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