How many PCI Express slots are there?
Generally 16 slots
Not too many people know that PCI Express (Peripheral Component Interconnect Express), officially abbreviated as PCIe, is a high-speed serial computer expansion bus standard designed to replace the older PCI, PCI-X, and AGP bus standards. Needless to say, physical PCI Express slots may contain from one to thirty-two lanes, in powers of two (1, 2, 4, 8, 16 and 32). It is extremely important to know that PCI Express operates in consumer, server, and industrial applications.