This is the 32-bit PCI Express ×16 slot on the motherboard. PCI Express architecture provides a high performance I/O infrastructure for desktop platforms with transfer rates starting at 2.5 Giga transfers per second over a PCI Express ×1 lane for Gigabit Ethernet, TV Tuners, 1394 controllers, and general purpose I/O. In addition, it provides a high performance graphics infrastructure, doubling the capability of existing AGP8X designs with transfer rates of 4.0 GB/s over a PCI Express ×16 lane.

When installing cards, ensure that the release latch, located at the right end of slot in this graphic, engages to secure the card.
When removing a card, release the latch before attempting to lift the card from the slot.