motherboard slots - DIMM - Wikipedia tt888 slot

The MSI X79A-GD65 (8D) is a high-end X79 motherboard featuring eight DDR3 DIMM slots and claims to be the first motherboard with support for PCIe 3.0.

The Motherboard may be showing it is configured to have 4 Slots, "soldered only 2 Physical Slots", the Operating System reads what the Motherboard is configured for; 4 Slots, but in fact only 2 Slots are in Operation.

Great motherboard, no Lan when both NVMe slots used.

PCIe (Peripheral Component Interconnect Express) slots are expansion slots found on a computer's motherboard ... This particular motherboard has 4 PCIe x16 slots, 1 PCIe x4, and 1 PCIe x1.