What is PCI-Express?

You can have the world’s fastest processors, the fastest memory, and the fastest access time to your stored data. If you don’t have the proper bus speed, you have a very expensive computer that provides no more power than its predecessors. No matter how fast your processors, memory, and peripheral devices are without the proper bus speeds, you will get minimal, if any, additional speeds.

This was the dilemma that has been a plague to PC development. No matter how fast, the bus speeds never really increased enough to match the new higher speeds. High speed buses used to be only a concern with graphic cards. They required direct access to the memory and the processor so that they could render the information quickly. The PCI organization (PCI-SIG) has developed several technologies to try to overcome the bus speed limitations. The latest and most widely accepted is that of the PCI Express bus.

Why should PCI Express be of any importance to people?
Any PC builder, technician, or seller should be aware of the changes in the PCI market. These changes affect the form factor, speeds, and implementation costs of the PCI connection. The old PCI connection is slowly fading. It was an old standard; back in the 90’s and is now considered to be no longer adequate to fit the speed and performance needs, in the new century. The graphics connection of AGP has been successfully ended by the PCI-SIG group and now exists on less than 5% of the available main boards. This means that the growing trend in main board development will see an increase in growth of PCI- Express connections.

What is PCI Express?
PCI Express changes how the bus communicates with peripherals and the rest of the computer. PCI Express is a serial connection that employs full duplex (sending and receiving) to double the effective speeds. PCI Express comes in many form factors, from PCI Express 1x to the server grade PCI Express 32x. The number before the ‘x’ indicates the number of communication lanes that the PCI Express bus uses. So 1x means that it uses one lane, while the 32x indicates it uses 32 lanes to send and receive data. Each lane represents a full duplex, serial communication that has speeds of up to 500 MBps.

The serial design decreases the cost of creating the cards; the full-duplex allows it to effectively double the speed of a single duplex connection with fewer raw materials. The connections are more reliable than the older parallel connections of PCI. PCI Express was also designed with lower power requirements. While some PCI Express cards do have their own power connections, it is not common. Most of the time these are only found on the most powerful of the PCI Express video cards.

Will PCI Express work with all of the connections that PCI does now?
Yes, PCI Express works with all of the connectivity types. Meaning you can find PCI Express network cards, video, sound, serial, parallel, USB, and more. PCI Express is also backwards compatible with other PCI Express cards. This means that if you have a PCI Express 8x connection you can use any PCI Express card of 8x or less.

PCI Express is the future for main boards.
The market has already seen a significant reduction in the AGP connection slot which is quickly being overtaken by the PCI Express form factor. These advancements are lowering costs and energy requirements while increasing the efficiency of computer peripherals. While many manufacturers are using a PCI and PCI Express side by side design, many of the higher end main boards are excluding almost all PCI connections. It is estimated that over the next 5 years, PCI will be as uncommon as its predecessor ISA.