PCIe Primer

A few years ago, AGP was the standard for high-performance graphics. But now, just a short time later, it's getting harder to find hardware that supports AGP. The world is moving to PCIe (PCI Express), and a lot of people don’t know much about it. Read on, as I explain what PCIe is, where it came from, and why you want it in your system.

As you have undoubtedly noticed, PCI Express contains the name PCI. But don’t be fooled by this; PCIe is not part of the standard PCI bus of your standard motherboard. More to the point, PCIe is another implementation of the PCI bus and even uses existing PCI programming concepts. But the similarities end there. PCIe is based on a much faster communication protocol. As a result, PCIe has more available bandwidth than almost all of the other internal buses, including PCI and AGP.

Although the specification for PCIe was finalized in 2002, it has actually taken quite awhile for PCIe to become mainstream. This movement started in 2004, and has been gaining momentum ever since. In the computer industry, adopting new standards takes time. Motherboard manufacturers don’t want to switch to a new standard until there are peripherals that can utilize these standards, because no one will buy the board. At the same time, peripheral manufacturers do not want to make a product that utilizes a standard that no motherboard supports. If all of the motherboards out there support AGP, then video card makers are going to continue making AGP cards, even if PCIe is faster. It’s simple economics, and also the reason why new standards are adopted more slowly.

So let's talk a little more about PCIe and where it came from.

Label: Hardware guides