When we start up our computer, PCIe will determine for us what are connected into the motherboard. Next, it will work to figure out the links between different devices and negotiate the width of each link. At the same time, it will find out the traffic map and coordinate the route of all traffic. As a matter of fact, PCI identifies devices and connects them in the same way. As a result, the old software and systems are still of use. And it is not necessary for you to change or upgrade your software or operating systems to make PCIe work on your computer.
Each lane of a PCI Express connection consists of two pairs of wires, and one for sending and one for receiving data. Packets of data can move across the lane at a rate of one bit per cycle. One lane of a x1 link, which is the smallest PCI e connection, contains four wires. It transmits one bit at once in each direction. A x2 connection is made up of eight wires and carries two bits per cycle. A x4 connection transmits four bits per cycle, and so on. There are also x12, x16 and x32 links whose operating can be inferred based on the same working principle.
PCI Express can be used by both desktop and laptop PCs. Its links uses fewer pins than PCI links do, which will decrease the cost of motherboard production. In this aspect, it is rather economical and convenient. On the other hand, chances are that it is compatible with many devices, for example, Ethernet cards, USB 2 and video cards. In all, PCI Express offers us more powerful digital systems which is able to help us deal with large amounts of data simultaneously, efficiently, and economically.