PCI Express x16 (graphics): PCI Express x16 slots are used mostly for graphics cards, though they can be used with any PCI Express card. Confusion may arise, however, because not all PCIe x16 slots are true PCIe x16. Occasionaly, you'll see PCIe x16 connectors that are physical slots for accommodating graphics cards, but are actually eight-lane (x8) or even four-lane (x4) electrically.
On some boards, even slots that support true 16-lane PCI Express for graphics may revert to eight lanes if you install a second graphics card into a second PCIe x16 slot on the motherboard. The P67 chipset, for instance, has only 16 total PCIe lanes for graphics. So if you drop in two graphics cards to run in dual GPU mode, each card will have just eight lanes available to it. This situation isn't as bad as it sounds, though, since even eight lanes in a PCIe 2.0- or 3.0-based system delivers plenty of bandwidth for most games.
32-bit legacy PCI slot: The now-classic 32-bit PCI slot has been around since 1993. A host of expansion cards support 32-bit PCI; and to accommodate them, most motherboards are likely to have at least one 32-bit PCI slot going forward. You may see some system boards configured so that a particular back-panel case bracket can support either a PCI slot or a PCIe slot, with some overlap between the two because they're very close together.
Front-panel switch header: This header connects various wires to the front panel of the case, where they link to power and reset buttons, and status LEDs for power and storage-drive activity.
Next: Motherboards for AMD CPUs and for the Intel Z77 chipset
Next we'll turn our attention to a motherboard that supports AMD CPUs. Note that AMD-chipset boards support many of the same features as Intel-based boards--that's the great thing about industry standards.
24-pin ATX power: This connector exists on all current ATX-based motherboards, and is the standard means of connecting power from power supplies. This connector delivers power to all interfaces, including 3V, 5V, and 12V. The typical ATX12V version 2.3 PSU delivers up to 75W for PCI Express graphics cards; but numerous modern graphics cards need more than that, which is why you'll often find secondary six- or eight-pin power connectors on the graphics cards themselves.
ATX4P: This unusual item is actually a SATA power connector for delivering power to SSDs, hard drives, or optical drives from the motherboard itself.
TPM connector: Some off-the-shelf PCs and laptops use the Trusted Platform Module connector to link to a cryptographic processor module for storing encryption keys and handling dedicated encryption chores such as hard-drive encryption and certain types of digital rights management (DRM) decryption.