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Motherboard Diagrams In Detail

A motherboard can be a very confusing looking component. This is because various hardware parts, connectors and power cables connect to it.

Amongst other things, it has a large panel of I/O connections, expansion slots (PCI and PCI-express), a chipset, various drive connectors, memory slots, power inputs, a power delivery unit, a processor slot and more!

Hence it is not surprising that many people find a motherboard to be confusing.

As a result, this article will show a labeled computer motherboard diagram and describe the various important parts of a motherboard. To get started, check-out the diagram below.

It has various numbers on it next to the most important parts (it won't cover all parts, but it'll cover the main and most common ones). Then see the numbered list below the diagram for a description of what each part is or does.

The motherboard being analyzed is the Gigabyte GA-P55M-UD2, a popular motherboard for the Intel Core i3 and i5 range. Many motherboards have very similar components and layouts though, so the exact motherboard being analyzed doesn't really matter.

Numbered motherboard diagram

  • Rear I/O - These are the external ports, for example the USB and other I/O (input/output) ports). The monitor, keyboard, mouse and speakers (along with other peripherals such as a printer) will slot in here. Despite appearing as though you are plugging these devices into the case, you are actually plugging them into this external part of the motherboard.
  • Power Input - Most motherboards are powered by a 24-pin ATX connector (see 12, below). However some modern motherboards require some extra power (especially for the CPU), hence this 8-pin power connector.
  • PCI Slots - These two light coloured components are the PCI slots. They are usually used to insert extra hardware components which are less powerful (in short, which have a lower data transfer/bandwidth rate than components which require a PCI-express slot). Examples include sound cards, modems and ethernet (network) cards.
  • PCI Express Slot - These two blue components are the PCI-Express slots. They have a higher data transfer/bandwidth rate than PCI slots and thus are used by higher-powered hardware parts such as a graphics card.
  • Battery - A motherboard holds various information about the system's configuation, along with the date and time. It is important that this data isn't lost even when the computer is switched off, hence this battery is used which ensures that such data doesn't get lost when the computer is turned off.
  • Processor - Once the lever is lifted, the CPU (the 'processor' - the 'brains' of the computer, i.e. where instructions are carried out and calculations are performed) is put into this socket. The CPU gives off a large amount of heat, and as a result a heatsink is installed over it (the four holes in all four corners of the CPU socket helps with the installation of certain heatsink's/CPU coolers).
  • Chipset - The chipset connects all the components on a motherboard and allows them to share data. As CustomPC (a magazine in the UK) says, "If the CPU is the brain of your PC then the chipset is the nervous system".
  • Memory/RAM Slots - These slots are where you install the memory/RAM sticks into your motherboard. They tend to be color coded because there's a certain order you should insert memory sticks depending on how many sticks you have.
  • USB Cable Slots - Many computer cases come with USB ports in the front. These are not part of the motherboard (unlike in 1, above) and so they need to be inserted into the motherboard - hence these slots.
  • Front I/O - Computer cases also come with various LEDs (lights showing hard-drive activity, for example) along with reset and power buttons. These also need to be connected to the motherboard, hence these cable slots.
  • Drive Connectors - This is where the various drives connect to your system. These include your hard-drive(s), optical drive(s) [for example CD/DVD drives] and - if you have a modern computer - solid-state drives (a newer, faster data storage device than hard-drives).
  • Power Input - This is the 24-pin ATX connector (as mentioned in 2, above). This is the main power connector for a motherboard and it powers much of the components attached to the motherboard (along with the electrical components - such as the chipset - on the motherboard itself). The 24-pin ATX connector comes from your computer's power supply unit (PSU).