SATA connectors: These components connect via cables to various storage devices, including hard-disk drives, solid-state drives, and optical drives.
IDE connector: Rarely found today, IDE connectors were used to link to older hard drives. In addition, until a couple of years ago, many optical drives supported IDE. Today, all new storage devices ship with SATA.
Floppy disk connector: The venerable 3.5-inch floppy disk drive survived for nearly two decades--an eternity in the tech universe. But unless you have a pile of old floppies, you won't need a floppy drive. And if you do find yourself needing a floppy drive, you can always pick up an external, USB-connected drive.
Now let's examine a more recent motherboard: an Intel D67BG, based on Intel's P67 chipset and supporting LGA 1155 CPUs (like the Sandy Bridge-based Core i7-2600K).
DDR3 memory sockets: Current-generation PC systems use DDR3 memory, but in many instances they support different operating speeds. The P67 chipset used in this board maxes out at DDR3-1600, but to achieve that level of speed you'd have to overclock the chipset--officially the P67 supports only DDR3-1333. Here, we see four memory sockets. The system supports dual-channel memory, meaning that the system is populated with paired memory modules, which are mounted in sockets of the same color.
CPU fan header: This connector is specifically designed to link to the CPU cooling fan. The system BIOS monitors CPU cooling fan speeds; and if the fan isn't connected to this header, you may get an error at bootup.
Eight-pin ATX12V (CPU power) connector: Back when the Pentium 4 processor first shipped, Intel realized that high-performance CPUs needed their own source of clean, dedicated power beyond what the standard 24-pin power connector could deliver. Thus was born ATX12V. You'll see four-pin connectors on lower-end boards supporting CPUs with lower thermal design power (TDP), but the eight-pin version of the connector is used with higher-end processors and on boards that users may overclock.
Power for secondary fans: Many motherboards with secondary-fan power headers; these connectors are mainly used to power and monitor various case fans.
PCI Express x1 connector: PCI Express is a serial interface, though multiple lanes may be ganged together. The "x1" refers to a slot supporting a single PCI Express lane; it is used for I/O devices that don't require bidirectional bandwidth greater than 500 megabytes per second (gen 1 PCIe). Sound cards, for example, are typically PCIe x1 devices.