CPU Socket Types Explained – From Socket 5 To BGA


Computer processors have a home. The socket. Most people ignore this piece of hardware because it has little obvious functional impact. Sockets don’t hinder or help performance they’re standardized in any given line of processors.

Why should you care? If you ever intend on upgrading your processor, the socket on your motherboard will limit the upgrades you can choose from. Sockets are also frame the future of hardware – their existence is part of the PC ecosystem, yet the socket is not guaranteed to live on forever.

What Is A Socket?

A processor socket is similar in function to a light socket. It’s an apparatus that is used to plug one item into a larger network of components. A light socket makes a light bulb part of an electrical network, giving the bulb the power it needs to work. A processor socket makes a processor a part your computer, both providing power and offering a way to transfer data from the processor to the rest of the PC.

Modern computers always place the CPU socket on the system’s motherboard. In the past some other configurations existed, including slot-mounted processors that were inserted like a modern PCI card. Today, however, sockets are simply that. A CPU simply drops into its socket and is secured with a latch.

Sockets have been around for decades. The original Pentiums used Socket 5 and the Intel 386, the company’s first famous processor, used a 132-pin PGA socket (I’ll explain the acronym shortly.) Sockets aren’t quite ubiquitous, however. Both AMD and Intel have flirted with slot-mounted processors in the past and numerous CPU companies build socket-less processors that are soldered on the motherboard.

Why Are There Different Sockets?
There are generally just a few types of light sockets, and they’ve been the same forever, yet processor sockets change all the time. What gives?

Changes to processor architectures are the reason. New architectures arrive every few years and often have different needs. And don’t forget there are two different major x86 processor manufactures, AMD and Intel, each with their own architectures. Compatibility between the two is impossible.

What Types Of Sockets Exist?
Many sockets have existed throughout history but only three are relevant today. These are LGA, PGA and BGA.

LGA and PGA can be understood as opposites. LGA stands for land grid array and consists of a socket with pins on which the processor is placed. PGA, on the other hand, places the pins on the processor, which are then inserted in a socket with appropriately placed holes. Intel uses the former while AMD uses the latter.

Then there’s BGA, which stands for ball grid array. This technique is used to permanently attach a processor to its motherboard during production, making future upgrades impossible. BGA is typically less expensive and requires less physical space than a socket-able processor.

BGA technically is not technically a socket because it’s permanent. It’s worth mentioning however, because it serves the same function and may become the socket’s replacement. Intel will start to ship more processors with BGA packaging by 2014 and ARM processor manufacturers, like Qualcomm and Nvidia, already rely heavily on BGA.

What Socket Sub-Types Exist?

A processor using a particular socket type will fit into any motherboard with that socket, right? Wrong!

Socket types like LGA are only a category rather than a specific model. There are many variations of sockets built on the basic design.

Intel gives its LGA sockets names based on the number of pins. LGA 1155, for example, has 1,155 individual pins on the socket. A processor built for a particular socket will only work with that socket even when the number of pins seems similar, as is the case with LGA 1156 and LGA 1155.

AMD takes a different approach. It labels its sockets with broad names like AM3 or FM1. Compatibility is once again strictly enforced, though AMD has occasionally upgraded a socket while retaining compatibility. When AMD does this it will add a “+” to the socket’s name, as with AM2+ and AM3+.

Will Sockets Become Extinct?

Computers are developed with the socket (or equivalent) as a core part of the design. Most components, including the processor, were to be serviceable or upgradeable. This gave both home users and large companies the opportunity to build a PC with whatever specifications were desired.

Now that dominant paradigm is challenged by the rise of mobile devices. While I don’t personally believe the PC is going extinct, I do believe it will change significantly. Part of this change may be the extinction of sockets. They add bulk and manufacturing complexity to products that strive to be as inexpensive and small as possible.

Predictions of the socket’s death in 2014 or 2015 are probably premature. Intel says it will move some focus to BGA but also continue to product socketable LGA processor. That makes sense. Enthusiasts that want to upgrade are a minority with money to spend.

With that said, however, the socket’s death does seem to be on the horizon. Efficient hardware will eventually make sockets seem unnecessary even to enthusiasts.

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