CPU socket

A CPU socket or CPU slot is a connector on a computer's motherboard that accepts a CPU and forms an electrical interface with it. As of 2007, most desktop and server computers, particularly those based on the Intel x86 architecture, include socketed processors.

Most CPU-sockets interfaces are based on the pin grid array (PGA) architecture, in which short, stiff pins on the underside of the processor package mate with holes in the socket. To minimize the risk of bent pins, zero insertion force (ZIF) sockets allow the processor to be inserted without any resistance, then grip the pins firmly to ensure a reliable contact after a lever is flipped.

As of 2007, land grid array (LGA) sockets are becoming increasingly popular, with several current and upcoming socket designs use this scheme. With LGA sockets, the socket contains pins that make contact with pads or lands on the bottom of the processor package.

In the late 1990s, many x86 processors fit into slots, rather than sockets. CPU slots are single-edged connectors similar to expansion slots, into which a PCB holding a processor is inserted. Slotted CPU packages offered two advantages: L2 cache memory could be upgraded by installing an additional chip onto the processor PCB, and processor insertion and removal was often easier. However, slotted packages require longer traces between the CPU and chipset, and therefore became unsuitable as clock speeds past 500 MHz. Slots were abandoned with the introduction of AMD's Socket A and Intel's Socket 370.

Many socket names containing three-digit numbers represent the number of pins on the processor or socket.

• DIP socket (40 contacts) - Intel 8086, Intel 8088
• PLCC socket (68 contacts) - Intel 80186^{[1] [2]}
• PLCC socket - Intel 80286
• PLCC socket - Intel 80386
• Socket 1 - 80486
• Socket 2 - 80486
• Socket 3 - 80486 (3.3 V and 5 V) and compatibles
• Socket 4 - Intel Pentium 60/66 MHz
• Socket 5 - Intel Pentium 75-133 MHz; AMD K5; IDT WinChip C6, WinChip 2
• Socket 6 - Designed for the 80486, but little used
• Socket 7 - Intel Pentium, Pentium MMX; AMD K6; some Cyrix CPUs

• Super Socket 7 - AMD K6-2, AMD K6-III; Rise mP6.
• Slot A - AMD Athlon
• Socket A (also known as "Socket 462") - AMD socket supporting Athlon, Duron, Athlon XP, Athlon XP-M, Athlon MP, Sempron, and Geode processors (PGA 462 contacts).
• Socket 754 - AMD single-processor socket featuring single-channel DDR-SDRAM. Supports AMD Athlon 64, Sempron, Turion 64 processors (PGA 754 contacts).
• Socket 939 - AMD single-processor socket featuring dual-channel DDR-SDRAM. Supports Athlon 64, Athlon 64 FX to 1 GHz^[3], Athlon 64 X2 to 4800+, Opteron 100-series processors (PGA 939 contacts). Superseded by Socket AM2 after about 2 years of launch.
• Socket AM2 - AMD single-processor socket featuring DDR2-SDRAM. Replaces Socket 754 and Socket 939^[3] (PGA 940 contacts, some confused Socket AM2 with "Socket 940" for server processors). Supports Athlon 64, Athlon 64 X2, Athlon 64 FX, Opteron, and Phenom processors.
• Socket AM2+ - AMD socket for single processor systems. Features support for DDR2 and HyperTransport 3 with separated power lanes. Replaces Socket AM2 (PGA 940 contacts, electrically compatible with Socket AM2). Supports Athlon 64, Athlon 64 X2, Athlon 64 FX, Opteron, and Phenom processors.
• Socket AM3 - Future AMD socket for single processor systems. Features support for DDR3 and HyperTransport 3 with separated power lanes. Planned to launch mid 2008. Replaces Socket AM2+ with support for DDR3-SDRAM (PGA 940 contacts).

• Socket 563 - AMD low-power mobile Athlon XP-M (µ-PGA 563 contacts, mostly mobile parts).
• Socket 754
• Socket S1 - AMD socket for mobile platforms featuring DDR2-SDRAM. Replaces Socket 754 for mobile processors (PGA 638 contacts).
• Socket FS1 - future Fusion processors for notebook market with CPU and GPU functionality (codenamed Swift), supporting DDR3 SDRAM, to be released in 2009.

• Socket 940 - AMD single and multi-processor socket featuring DDR-SDRAM. Supports AMD Opteron^[3] (2xx and 8xx Series), Athlon 64 FX processors (PGA 940 contacts).
• Socket A
• Socket F (also known as "Socket 1207") - AMD multi-processor socket featuring DDR2-SDRAM. Supports AMD Opteron^[3](2xxx and 8xxx Series) and Athlon 64 FX processors. Replaces Socket 940 (LGA 1207 contact), and partially compatible with Socket F+.
• Socket F+ - Future AMD multi-processor socket featuring higher speed HyperTransport interconnect of up to 2.6 GHz. Replacing Socket F but socket F processors remained supported for backward compatibility.
• Future processor which is in development under the Fusion project codename, will employ Socket FS1 and two other sockets.
• Socket G3 - successor to socket F+, paired with Socket G3 Memory Extender for servers to expand memory.

• Slot 1 - Intel Celeron, Pentium II, Pentium III
• Socket 370 - Intel Pentium III, Celeron; Cyrix III; VIA C3
• Socket 423 - Intel Pentium 4^[4] and Celeron processors (Willamette core)
• Socket 478 - Intel Pentium 4, Celeron, Celeron D, Pentium 4 Extreme Edition^[4], Pentium M
• Socket N (Northwood, Prescott, and Willamette cores)
• Socket B (LGA 1366 ^[5]) - a new socket for future Intel CPUs incorporating the integrated memory controller and Intel QuickPath Interconnect.
• Socket T (also known as Socket 775 or LGA 775) - Intel Pentium 4, Pentium D, Celeron D, Pentium Extreme Edition, Core 2 Duo, Core 2 Extreme, Celeron^[4], Xeon 3000 series, Core 2 Quad (Northwood, Prescott, Conroe, Kentsfield, and Cedar Mill cores)
• Socket H (LGA 715) - a future replacement for the current Socket T (LGA 775), without integrated memory controller and newer point-to-point processor interconnect.

• Socket 479 - Intel Pentium M and Celeron M (Banias and Dothan cores)
• Socket 495 - Also known as PPGA-B495, used for Mobile P3 Coppermine and Celerons ^[6]
• Socket M - Intel Core Solo, Intel Core Duo and Intel Core 2 Duo
• Micro-FCBGA - Intel Mobile Celeron, Core 2 Duo (mobile), Core Duo, Core Solo, Celeron M, Pentium III (mobile), Mobile Celeron
• Socket P - Intel-based; replaces Socket 479 and Socket M. Released May 9th, 2007.

• Socket 8 - Intel Pentium Pro
• Slot 2 - Intel Pentium II Xeon, Pentium III Xeon
• Socket 603 - Intel Xeon (Northwood and Willamette cores)
• Socket 604 - Intel Xeon
• PAC418 - Intel Itanium
• PAC611 - Intel Itanium 2, HP PA-RISC 8800 and 8900
• Socket J (also known as Socket 771 or LGA 771) - Intel Xeon (Woodcrest core)
• Socket N - Intel Dual-Core Xeon LV

• Socket 463 (also known as Socket NexGen) - NexGen Nx586
• Socket 499 - DEC Alpha 21164A
• Slot B - DEC Alpha 21264
• Slotkets - adapters for using socket processors in bus-compatible slot motherboards

• List of Intel microprocessors
• List of AMD microprocessors

• CPU Sockets Chart - A fairly detailed table listing x86 Sockets and associated attributes.
• techPowerUp! CPU Database
• Processor sockets