Answer Description
PCIe, or PCI-Express, comes in x1, x4, x8, x16, x32 speeds.
Wikipedia
PCI Express (Peripheral Component Interconnect Express), officially abbreviated as PCIe or PCI-e, is a high-speed serial computer expansion bus standard, designed to replace the older PCI, PCI-X, and AGP bus standards. PCIe has numerous improvements over the older standards, including higher maximum system bus throughput, lower I/O pin count and smaller physical footprint, better performance scaling for bus devices, a more detailed error detection and reporting mechanism (Advanced Error Reporting, AER), and native hot-plug functionality. …
PCI Express - Wikipedia, the free encyclopedia