A CPU -- the green square with rubber pads in the corners -- seated in a CPU socket.
CPU sockets are standard in both desktops and laptops. There have been many different types of CPU sockets over the years and they continue to change regularly. Intel is famous for changing its socket types with almost every new product line, making it necessary to purchase a new motherboard every time you want to upgrade. By contrast, AMD usually keeps its processors compatible with a single socket type for several years, making upgrades much cheaper and easier.
AMD AM3
The AM3 socket is used for most of the newer quad and hex-core processors from both the Athlon II and Phenom II products lines. It is a 941-pin socket designed to replace the AM2 socket and the migratory socket AM2+. The main difference between the AM3 socket and compatible CPUs is that it is designed to work with DDR-III memory.
AMD AM2+
The AM2+ was designed as a midway migration socket type to assist the changeover from AM2 to AM3. The socket succeeded the AM2 socket to provide memory controllers for both DDR-II and DDR-III memory, making it possible to work with both AM2 and AM3 processors. However, an AM2 processor will not function in an AM3 motherboard due to the lack of a DDR-III memory controller.
AMD AM2
AM2 was introduced in 2006. It was the previous 940 pin socket with a DDR-II memory controller and support for older Athlon and Phenom processors. The socket was one of the longest lasting designs. AM2 processors will work in both AM2 and AM2+ sockets, although not in an AM3 socket.
Intel LGA1155
The Intel LGA1155 replaces the previous LGA1156 socket. It is the standard socket for many of Intel's Core i3, i5 and i7 CPUs in addition to its server CPUs from the Xeon line. The socket is not backwards compatible with its predecessor in spite of the apparent similarity. Only the cooling systems are interchangeable. LGA is short for "Land Grid Array."
Intel LGA1366
The highest end processors from the Core i7 range use the Intel LGA1366 1366-pin socket. Some server systems also use this socket.
Older Socket Types
CPU sockets which are no longer supported or available include the LGA775, Socket 370, Socket 423 and Socket 479 for Intel CPUs and the Socket 939 and Socket A for AMD CPUs.
Tags: DDR-III memory, Socket Socket, Athlon Phenom, compatible with, Intel LGA1155, Intel LGA1366, memory controller