expansion slots on motherboard
My brothers pc has twelve ram slots and why? : r/PcBuild
The slots on a motherboard are either designed for a specific component, such as memory or storage, or designed for general expansion.
Which PCIe Slot is best for your Graphics Card? - CGDirector
The width of a graphics card is often expressed in terms of "slots," which indicates how many expansion slots it occupies on a motherboard.
What use are PCI slots apart from for the graphics card?
A motherboard usually had five or so PCI expansion slots. The more expansion slots it had, the more devices your computer could connect to.