What is this slot for on my motherboard? It's a Micro Star Pro z790a I

microstar slotThe 611 (PCIISAAGP) slot confuration works with the 4 DIMM slots to make this the most expandable i440BX motherboard to come through the AnandTech lab.The 611 (PCIISAAGP) slot confuration works with the 4 DIMM slots to make this the most expandable i440BX motherboard to come through the AnandTech lab.