If the CPU is a computer’s brain, the motherboard is its nervous system. Most of your other components will plug into the motherboard, so the one that you use in your build needs to be exactly what you need now, and what you expect to need from it in the future.
Socket type. A motherboard’s socket type must match that of the CPU you plan to use in it. Always cross-compare.
Form factor. Motherboards come in a range of form factors, which determine how many other components you can install and what kind of case you need. For most full-size desktop builds you’ll probably want either Micro ATX or ATX; for smaller builds, Mini ITX will work.
Memory. You need to know the memory type and standard your motherboard uses, which are usually listed together; just buy what it supports and you’ll be fine. (Ignore “O.C.” numbers if you don’t plan to overclock your memory.) The number of memory slots tells you how many individual modules, or DIMMs, you can use; you’ll also see the maximum memory supported. A motherboard labeled dual-, triple-, or quad-channel supports a CPU technology that delivers increased performance if you fill enough of the RAM slots.
Expansion slots. The ATX and Micro ATX motherboard form factors have between four and seven PCI Express (PCIe) slots, for adding expansion cards. These may use either the current top-end standard, PCIe 3.0, or the older 2.0, with designations based on the size of the slots and the number of PCIe lanes they use. The longest and fastest slots are x16, though some that look identical may run at x8 or x4; in addition, there are visibly smaller x1 slots. On a Mini ITX motherboard, expect only one x16 slot.
Storage. SATA remains the most common interface for connecting internal storage devices. The newest version of the standard, SATA 3, supports data transfer rates of up to 6Gbps. You may also find some other interfaces; M.2, in which a flash-based storage module plugs directly into a thin slot on your motherboard, is becoming increasingly popular. Regardless, you’ll want to have enough of the right kind of ports for whatever storage you want to buy.
Onboard technologies. All boards have USB ports, sound output, and Ethernet; most include integrated Wi-Fi and/or Bluetooth; and many have ports for taking advantage of lower-end processors’ integrated video capabilities. It’s worth checking the specs so that you don’t forego something you really want.
Video card support. Think you may want to concoct an ultra-powerful gaming machine with more than one graphics card? Even if you have enough slots to hold multiple cards, your motherboard must be designed for use with either Nvidia’s SLI technology or AMD’s CrossFireX, so verify that first.