Mini-PCIe slots provide a small & adaptable way to expand a computer system's functionality without taking up a lot of room. Flexibility & Personalization. All things considered, a variety of expansion card requiremslots on lineents are met by the various PCI slot types, ranging from small wireless adapters to high-performance graphics cards. This diversity enables users to tailor their computer systems to meet their unique needs, be they networking, gaming, or multimedia production. PCI slots are essential to gaming systems because they provide high-performance graphics cards and other gaming-related hardware components the connectivity they need.