apg slotOlder Expansion Slots on Motherboards 1. AGP Slot. Stands for Accelerated Graphics Port, this slot is available only in older motherboards to connect the graphics card for accelerating 3D output. AGP offers faster[Peter] has a Socket 7-based NAS with an AGP slot, and was left wondering whether the unused port could be put to a worthwhile purpose. AGP is a superset of