Out of all the common PC parts, I’d argue motherboards are the most convoluted. You have to consider so many things: form factor, connectivity, PCI-e, chipset, power delivery, VRM cooling, extra features, and more. Seeing as new motherboard generations for either Intel or AMD come out at least once per year and Alder Lake chips are all the rage, here is everything you need to know about motherboards.
If you don’t know what a motherboard is, it’s basically where everything plugs or slots into. It distributes power from your power supply between all the other parts in your system, and it defines which parts can be used.
Motherboards come in four main form factors, each with its own advantages and compromises. You will need to make sure your motherboard fits inside your case. You don’t want to get a motherboard too big for your case, and you don’t want a motherboard so small in comparison to your case that it looks silly. mini-ITX is the smallest major form factor. What ITX boards lack in connectivity, they make up for with compactness. They fit in all except the most extreme small-form-factor cases, and they’ve gotten so good today that they’re often indistinguishable from ATX boards in terms of features and VRMs. micro-ATX boards seem to be waning in popularity. They’re the next size up, and they’re generally the cheapest form factor. mATX boards fit in mATX cases, which are also the cheapest cases. If you’re on a tight budget, you might consider the micro-ATX form factor. ATX motherboards have always been the most popular. ATX is the standard size, and they come fully loaded with high-end features if you have money to spend. The largest form factor is extended ATX (eATX), which is really the SSI-EEB server form factor. eATX boards are typically only the most extreme boards for over-the-top high-end builds, so most people should not consider them. Their additional features over ATX, or even mini-ITX at this point, are limited.
People often mistakenly use the terms “socket” and “chipset” interchangeably. However, there are often multiple chipsets per CPU socket. AM4 is AMD’s current mainstream socket, and all AMD CPUs with the current pin (all Ryzen chips) layout fit in the AM4 socket. However, there have been many chipsets since the launch of AM4, from B350 and X370 to B550 and X570. Despite all AM4 CPUs and boards having the same pin layout, not all AM4 CPUs work on all motherboard chipsets within AM4. This is because CPUs require BIOS support from the motherboard manufacturer. If you try to use a CPU that is not supported by the motherboard, you could fry your board. So be sure to use PCPartPicker to determine compatibility.
You will often see a motherboard chipset marketed with its PCI-e generation (PCI-e 5.0, 4.0, 3.0, etc.). PCI-express is an interface standard (slot shape) for GPUs, RAID cards, Wi-Fi cards, or certain SSDs. Bandwidth roughly doubles each PCI-e generation, meaning transfer speeds of data increase as the generation increases. PCI-e 5.0 is supported on Intel Z690 motherboards, but it is a useless feature since there are currently no PCI-e 5.0 compatible SSDs or GPUs. As such, PCI-e 4.0 is the fastest you can use right now, and it is supported on all current mainstream motherboards. PCI-e slots also come in different physical sizes: x1, x4, x8, x16, and x32. The number indicates how many PCI-e lanes a slot has. The number of lanes determines how much data can be transferred at once. Most GPUs require an x8 or x16 connection, and that’s why you should always slot in your GPU in the top PCI-e slot on your motherboard. If you put an x16 GPU like a 3080 in an x8 slot, it will run slowly. Finally, PCI-e bifurcation means splitting one slot’s lanes in two halves. So an x16 slot could support two x8 SSDs connected via an add-in SSD card in that one slot. Essentially, make sure that if you have a PCI-e 4.0 SSD, you get a PCI-e 4.0 or 5.0 motherboard. The same goes for GPUs.
There are dozens of tiny slots and connectors on your motherboard. Make sure you get what you need. For example, if your case has a USB-C slot, you should get a motherboard with a front USB-C header. Similarly, if you have tons of RGB, make sure your motherboard has lots of ARGB connectors (or get an ARGB hub). Typically, you will find your rear I/O connectors in the top left of your board. They will face towards the back of your case. You will also find your CPU 8-pin power connector and a massive VRM heatsink that supplies power to the CPU. In the top right, you will find your memory DIMM slots and your motherboard 24-pin connector. In the bottom right, there are SATA ports (for HDDs, SSDs, and other internal accessories/peripherals), front panel headers, and internal USB headers. The bottom right also has the chipset, which is a communication interface between your CPU and other components. Sometimes the chipset will have a small fan over it to keep it cool. Finally, the bottom left of a motherboard features PCI-e and M.2 slots. In the top-middle of your board is the CPU socket.
Next we will move on to features that may make or break your buying decision. The CPU gets its power through a voltage regulator module (VRM). The VRM ensures that your CPU and GPU receive clean power at a consistent voltage. It converts power supply 12-volt power down to 1.1-1.5 volts for your components. Inside the VRM heatsink and/or around the CPU socket are MOSFETs, chokes, and capacitors, the three components of a VRM. Modern computers require multi-phase VRMs. The more phases, the more stable the voltage is. Power phases are often labeled 8+2 or 12+3. The first number indicates how many phases are dedicated to the CPU, and the second number is the number of phases allocated to all the other components. Often, many boards with more than eight phases use phase doublers, which increase the number of phases. A 16-phase board using doublers can deliver more power than an 8-phase board without doublers, but the 8-phase board may deliver a more stable voltage, depending on the quality of the VRM components. Luckily, you don’t have to keep track of all these complicated phrases, as in general the more money you spend within a motherboard chipset, the better VRM you get. You may have seen manufacturers market 4-layer, 6-layer, or even 8-layer PCBs. But what does this mean? PCB layers are the conductive copper layers in the board. 4-layer PCBs are the easiest and cheapest to manufacture, while 6-layer and 8-layer PCBs are more expensive. The more PCB layers, the more directly critical traces (connections between components) can run and the better your components will overclock. 6-layer designs are a nice sweet spot, as you can usually find 6-layer B550 ATX boards for around $180, or $160 if you look hard enough.
Every manufacturer has its own basic input/output system (BIOS). Technically, a BIOS is a chip on your motherboard that allows you to access and set up a computer at the most basic level. However, to most users, the BIOS is really the BIOS setup, or UEFI, which is a program that your computer boots to when it first completes the power-on self-test (POST) after you have built it. The BIOS setup allows you to configure hardware settings before you boot into Windows for the first time. The data on a BIOS chip can be updated in two ways. If your board has a BIOS flashback or clear CMOS button and you need to update the BIOS for your system to power on, you can install a new BIOS from the motherboard manufacturer’s website onto a USB stick using another computer, then insert the stick into the BIOS flashback USB port on your rear I/O and press the BIOS flashback button. If you do not have this feature or you have it but your computer already powers on, you should still update the BIOS occasionally. BIOS updates can fix issues with your computer that cannot be fixed with new drivers or a system software update. You can update the BIOS on an already functioning computer by installing the BIOS onto a USB stick, then booting into the BIOS setup, inserting the USB stick, and using the firmware update tool to update the BIOS. Some BIOS setup interfaces are better than others. BIOS setups differ in terms of overclocking or other control features, as well as ease of use and navigability. Asus generally has the best BIOS setup, but I would not recommend buying a motherboard only because of the ease of use or feature set of its BIOS.
Every motherboard has two to four DIMM slots in the top right that house your memory, or RAM sticks. Generally speaking, more DIMM slots is better, but it’s not that simple. In reality, more memory channels is better. The more channels, the faster the data transfer rate between the DRAM memory and the memory controller on your motherboard. You’re best off putting one RAM stick per channel. Most ATX and mATX motherboards have two memory channels, so you can use two or four RAM sticks, but using just one will hinder your performance (you also usually want to use slots two and four if you’re using two sticks). Most ITX boards with two slots nowadays also have two channels, so you should populate both slots. In the rare case both your CPU and motherboard support quad-channel memory, you should use four RAM sticks to maximize performance. Intel Z690 boards support new DDR5 memory, which has fast transfer speeds but high latency. Since DDR5 is not much faster than DDR4 but is way more expensive, I’d wait until prices and latencies come down before you buy it. Each motherboard can only support one generation – DDR4 or DDR5 – of memory, so make sure you get DDR4 memory if you get a DDR4 board and DDR5 if you get a DDR5 board. Last up are the memory speeds, measured in megahertz (MHz). The faster your RAM, the faster it transfers data to other components. However, most motherboards don’t support the fastest RAM speeds (4400 MHz and higher), so make sure your motherboard and RAM are compatible. I would always recommend enabling XMP or DOCP in the BIOS setup to get the most out of your RAM kit, and this can be done on pretty much any mainstream current-generation motherboard.
Motherboards vary greatly in rear I/O connectivity. Cheap motherboards often lack an I/O shield. They also often have less USB ports, slower Ethernet ports, worse audio controllers for the headphone jacks, and no USB-C or BIOS flashback. They also often lack Wi-Fi, which is not necessary for most due to Ethernet. Thunderbolt is a connection interface between a computer and external peripherals. Thunderbolt ports have the USB-C form factor, but they are much faster at transferring data. While this may not sound like a big deal, Thunderbolt ports offer enhanced capabilities for connecting external monitors, external GPUs, external hard drives and SSDs, and more. Thunderbolt 3 is twice as fast as the fastest standard USB-C ports, and the new Thunderbolt 4 is the same speed but it can transfer more power and data to peripherals. The problem with Thunderbolt is that it’s an Intel technology, so only a few select AMD motherboards have it. Additionally, no AMD laptops support Thunderbolt. While it’s not a dealbreaker, some people genuinely need Thunderbolt, so make sure you align your purchase decision with your needs and use case.
You’ve probably heard that SLI is dead, but I’ll touch on it briefly. NVIDIA SLI and AMD CrossFire are connection technologies that allow two of the same GPU model to act as one, increasing performance slightly. AMD CrossFire was eliminated in 2017, while SLI technically still exists, but only on the RTX 3090. Most new motherboards still support both SLI and CrossFire, which can be useful to the few people that have either two old AMD GPUs, two old NVIDIA GPUs, or two top-tier current-generation NVIDIA GPUs.
The last motherboard selling point is its extra quality-of-life features. M.2 shields (cool your SSD), POST codes (two-digit code that tells you what is wrong with your PC if it won’t boot), more USB ports, faster Ethernet, troubleshooting LEDs (similar to POST codes but less specific), BIOS flashback, I/O shields, overclocking protections, motherboard water cooling (some boards have a water block on the VRM instead of a heatsink), better audio controllers, RGB (and RGB softwares like Asus Aura Sync), more M.2 slots (for fast SSDs), built-in Wi-Fi and Bluetooth, front panel headers like front USB-C, and more fan headers are examples of key features you may genuinely need.
Now that I’ve told you everything you need to know about motherboards as a beginner or intermediate PC builder, it’s up to you to evaluate what you need and want. How much are you willing to spend? Do you want full-sized ATX or do you want to save money and go mATX? How many USB ports do you need? Is your RAM compatible with the motherboard you’re considering purchasing? Do you need the highest-end X570 or Z690 chipset, or will B550 or B660 work for you? These are all questions you need to answer before buying a motherboard in 2022. Feel free to ask me any questions you may have about a specific motherboard. I would be happy to recommend a board for you that fits your needs or has good value.
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