PCI Express 2.0 is a high-speed interface standard used to connect various hardware components in a computer, such as graphics cards, storage devices, and network cards. It offers a significant increase in data transfer rates compared to its predecessor, PCI Express 1.0, allowing for faster communication between the motherboard and connected devices. This version supports a maximum bandwidth of 5 GT/s (gigatransfers per second) per lane, effectively doubling the speed of PCI Express 1.0. PCI Express 2.0 maintains backward compatibility, meaning older devices can still function on newer motherboards that support this standard.