CPU Socket – What you need to know to avoid confusion

Definition of Socket CPU

A CPU socket is a type of slot (base, whatever you call it) to install a central processor (CPU). Each CPU line will have a different socket type. A socket is usually composed of 1 or more mechanical parts. Those details connect the CPU to the circuit board (mainboard) through mechanical and electrical connections. This allows you to easily replace the CPU without having to de-solder the board.

Some types of sockets use clamps. That forces the user to apply steady force for it to activate the retainer. For some current types of sockets that have many pin pins, when installing, you do not need to apply force. Keeping the CPU in the socket will be done by retention mechanisms. This will provide better holding force than the previous clamping mechanism without the fear of bending the legs.

Types of CPU sockets

There are 2 main types of sockets that we will learn about today:

Land Grid Array (LGA)

Overview

LGA socket type (Abbreviation for Land Grid Array) is a type of CPU socket designed in such a way that the pins are placed right in the socket, instead of being placed on the CPU and LGA CPUs can use both socket mounting and soldering on the motherboard. And LGA can support more pins. From there, it follows that we will have more pin pins, allowing better power supply to the CPU.

This socket type was first used in 1996 with the MIPS R10000 and HP PA-8000 CPUs. But this socket type was not popular until Intel started applying it on the Pentium 4 generation in 2004. And from Q1/2006, the server segment, represented by the Xeon line, also switched to the LGA socket type. Since then, most Intel CPUs have used this socket type.

AMd also introduced the first CPU line using LGA model in Q2/2006 called Opteron for Server array. They still use the PGA type for normal desktop CPUs. And on August 10, 2017, AMD introduced TR4 – the first LGA-style socket for the consumer segment after so many years.

​ List of LGA sockets

In the lists below, I only mention popular socket types. Similarly, in the compatible chipset section, only common chipsets are listed.

Intel

Note:

Socket 771 CPU can be installed into Socket 775, with an adapter and minor modifications to the socket

Although they have the same socket 1151, Skylake/Kaby Lake CPUs are not compatible with Coffee Lake mainboards and vice versa. Mod BIOS can remove this limitation. However, I do not encourage you to do it

Starting from Socket 1151 (universal) and Socket 2066 (HEDT/WS) generations onwards, Xeon CPUs will only be usable with their own main chipset.

LGA2011 CPUs are not compatible with LGA2011-3 and vice versa, even though they have the same pin number.

AMD

Note:

Even though it is one, the EPYC CPU (Socket SP3) cannot work on the main thread for Threadripper (Socket TR4) and vice versa.

Threadripper 39xx CPUs (sTRX4, TRX40 chipset) cannot run on TR4 mains (X399 chipset), even though the physical socket diameter is the same.

Pin Grid Array (PGA)

Overview

If LGA is the pin inside the socket, then PGA is the exact opposite. For PGA, the pin pins will be located below the CPU, and on the socket are small holes to plug those pin pins into. Pin pins are usually spaced 2.54mm apart and may not cover the entire bottom of a CPU. There is a disadvantage to this type of socket, which is that it cannot cram in as many contact pins as LGA. Additionally, you must be extremely careful when handling PGA CPUs.

There are many types of CPUs for PGA sockets, typically:

Plastic Pin Grid Array (PPGA)

Flip-chip Pin Grid Array (FCPGA)

Staggered Pin Grid Array (SPGA)

Ceramic Pin Grid Array (CPGA)

Organic Pin Grid Array (OPGA)

Stud Grid Array (SGA)

Reduced Pin Grid Array (rPGA)

Among them, FCPGA is still commonly used on AMD CPUs and some Intel laptop CPUs to this day. Among them, AMD is the largest user. The PGA socket that AMD uses is designed with zero insertion force (ZIF). That is, you just need to align the hole and gently drop the CPU into the Socket and you’re done.

List of PGA socket types

Like LGA, I will only mention popular socket types. Similarly, in the compatible chipset section, only common chipsets are listed.

Intel

Note:

Socket 7’s CPU can be installed into main Socket 5 if using an adapter or breaking the CPU pin.

Similarly, CPU Socket 478 can be installed into Main socket 423 if there is an Adapter

AMD

Note:

Super Socket 7 is backward compatible with Socket 5 and Socket 7 CPUs

Socket AM2 CPU is compatible with AM2+ main and vice versa, AM2+ CPU is compatible with AM2 main

AM3 CPU is compatible with AM2/AM2+ mainboard via BIOS update. But CPU AM2/AM2+ is not compatible with main AM3.

Epilogue

So we have learned what a CPU socket is and what types of sockets there are. Hopefully this article will help you in the process of choosing to buy computer components for your system.