PCI Express is a new generation of bus interface. In the spring of 2001, Intel is put forward to a new generation of technology to replace the PCI bus and the inner connection of a variety of chip, and is called the third generation I/O bus technology. At the end of 2001, Intel, AMD, DELL, IBM, more than 20 industry leading companies started drafting the specification of the new technology, and completed in 2002, officially named the PCI Express.

There are so many people feel confused about the different specifications of this brand-new bus interface, cannot fully understand the difference between them. For solving the problem, this article will detailed introduce the definition, parameters, compatibility and some related concepts of PIC-e. We hope that it will be helpful for readers. 

Definition of PCI Express:

PCI Express（Peripheral Component Interconnect Express）(officially abbreviated as PCIe) is a high-speed serial computer expansion bus standards, designed to replace the old PCI, PCI - X and the AGP bus standard. Compared to the older standards, PCIe has many improvements, including a higher maximum throughput of the system bus, the lower the number of I/O pins and a smaller physical footprint area, better bus equipment performance scale, more detailed error detection and reporting system (senior error reporting, AER) and local hot pluggable function. The latest revision of PCIe standard provides hardware support for the I/O virtualization

Modes of PCI Express：

PCI Express has several different modes, classified by transmission lanes: PCI Express x1, PCI Express x4, PCI Express x8, PCI Express x16. Please check the detailed parameters table.

Difference between PCI Express x1, x4, x8, x16：

Simply speaking, the difference between them is:

'PCIe x1' connection has one data lane

'PCIe x4' connection has four data lanes

'PCIe x8' connection has eight data lanes

'PCIe x16' connection has sixteen data lane

The more data lanes in the connection, the greater the bandwidth between the NIC and the host, and the higher the cost.

PCI-E × 16 is used to install PCIE interface dedicated graphics card

PCI-E × 8 is used to insert solid-state hard drive

PCIE × 4 is the sound card

PCIE × 1 is to install a small PCIE interface expansion card, such as network cards, TV cards

PCI Express Compatibility：

PCI Express is compatible with current PCI technologies and devices at the software level, supporting the initialisation of PCI devices and memory modules, which means that current operating systems do not need to be overridden to support PCI Express devices. PCI Express is a new generation of new architectures that deliver a large amount of bandwidth and rich functionality for exciting new graphics applications. PCI Express can allocate bandwidth for bandwidth-hungry applications and dramatically increase the bandwidth between the central processing unit (CPU) and the graphics processing unit (GPU). For end-users, they can experience cinematic picture effects and a seamless multimedia experience.

Of course, in addition to PCI Express definition, mode and compatibility, there are other related concepts you need to understand, which you can more fully understand the PCI Express.

What is PCI Express slot？

PCI-E slot name is "PCI-Express", is the latest bus and interface standards, its original name "3GIO", proposed by Intel, it is clear that Intel means that it represents the next generation I / O interface standard. After PCI-SIG (PCI Special Interest Group) certification was renamed "PCI Express". This new standard will completely replace the current PCI AGP, and ultimately the unity of the bus standard. Its main advantage is the high data transfer rate, the current maximum of 10GB / s or more, but there is considerable potential for development. PCI Express also has a variety of specifications, from PCI Express 1X to PCI Express 16X, to meet the present and future the low-speed equipment and high-speed equipment needs. Supporting for PCI Express is mainly Intel's i915 and i925 series chipset. PCI-E slot transmission speed is faster, and is also the future development trend. According to customer demand, with the introduction of three-dimensional VGA capture card using PCI-E slot, they are widely used in the medical, recording and broadcasting, video conferencing, distance learning and other industries.

Summary：

By introducing the definition, model, compatibility and related concepts of PCI Express, I believe that readers has a more comprehensive understanding of the purchase of PCI Express, so that can choose the most suitable one for their needs.