What Is a Motherboard?

The CPU is often thought of as the brain or heart of a computer. On its own, however, a CPU is little more than a beautifully etched silicon wafer wedged between a metal plate and a circuit board. While it has a small amount of integrated cache memory, it needs to be connected to the rest of a computer to function. The motherboard forms the backbone of the computer. Most PC components connect directly to the motherboard, with everything else connecting to it indirectly.

Components

Near the centre of the motherboard, you have the CPU socket, in which the CPU needs to be mounted. Nearby, the motherboard also features all of the power transformers required to keep the CPU operating smoothly, even when running at full tilt. On one or two sides of the CPU, you’ll find the RAM slots, these are typically very close to minimise signal travel time. The chipset controls connectivity to peripherals and storage. PCIe slots offer ultrahigh-speed connectivity for add-in cards. Rear panel connectors provide connectivity options. There is also a range of internal headers for fans, addressable RGB lighting, liquid cooling pumps, and the like. Power connectors are also critical, taking power directly from the PSU and distributing it to all other components.

Connecting directly to the motherboard you have the CPU, RAM, M.2 storage drives, and add-in cards such as graphics cards. These are often carefully positioned to be as close as possible to the CPU to minimise signal propagation delay for optimum speed and performance. Some devices that connect to the rear panel connectors may also be directly connected. For example, USB network cards and storage.

Many devices connect to the motherboard via cables. These include SATA storage drives, case and radiator fans, and addressable RGB lighting. Some peripherals may also connect via cables, if they’re connected via the rear panel, this could include speakers or keyboards and mice.

The last set of devices connects entirely secondarily. For example, monitors typically connect directly to the graphics card, though systems with integrated graphics can offer direct connectivity from the rear panel. The front panel connectors, are used for greater accessibility, and typically take the form of a USB hub, offering audio connectivity, and occasionally more.

Form factor

The motherboard dictates the size of the computer case and to some degree the other components. There are some motherboards that are designed to have all the bells and whistles. These are obviously expensive and large. This means a large case is required. The large case and the abundant connectivity, however, means that there’s very little limitation on component selection.

Some computers, however, don’t need to be so fancy and are instead designed to take up as little space as possible. These are small form factor computers. Because of the size constraints of small form factor cases, cooling options are often more limited. This, however, means that less motherboard space needs to be dedicated to power management, allowing a surprising number of components to be attached.

Chipset and socket confusion

Each CPU is shaped in a very specific way and has a precise number of connector pins on the bottom. They are designed to fit in exactly one type of socket. Other sockets, are the wrong shape, or feature the wrong number of connector pins and are simply incompatible. To allow easy drop-in CPU upgrades, AMD has opted to rarely upgrade its CPU socket. This means you can buy CPUs three generations apart and have them fit in the same motherboard.

The issue with this is that each generation of processors comes with a new chipset. The chipset affects the connectivity that the motherboard can offer. While slow socket upgrade cycles can allow new CPUs to simply provide a drop-in upgrade, often some new features won’t be compatible with the older motherboard.

Intel goes the opposite way from AMD. It updates the CPU socket every two generations. This almost certainly means you need to buy a new motherboard and CPU if you want to upgrade. It does, however, mean you tend to get all of the latest features supported.

Unhelpfully, though CPU sockets tend to have unwieldy names such as LGA1700 or AM4. This can mean that uninformed buyers who don’t know to check for this specifically, can purchase motherboards with sockets that don’t fit their CPU.

There’s the same problem with chipsets too. Chipsets often get codenames like B560, B650, B660, and Z690 which belong to Intel, AMD, Intel, and Intel respectively. Buyers that aren’t keenly aware of exactly what they need may find it easy to get the wrong product or a product in a different tier from what they were wanting.

Conclusion

The motherboard is the spine of a computer, connecting everything together and enabling communication. Care needs to be taken to ensure compatibility with the CPU. The case should also be a compatibility consideration as motherboards come in a range of small and large sizes. Outside of compatibility factors, motherboards also carry a broad array of features directly that can make deciding which model to get a time-consuming process.