Good-bye PCI, hello PCI Express

One of the most comprehensive refreshes of Intel architecture will start rolling out this summer. The PCI Express bus will replace current I/O interfaces, such as PCI for device interconnects and AGP8X for graphics, on all servers, workstations, desktops, notebooks, and communications devices.

According to Jim Pappas, director of technology initiatives at Intel, one of the main reasons for the switch is to enhance network performance.

“As servers move to 10GbE, PCI runs out of steam and PCI Express picks up,” Pappas said.

Initially, most desktops and servers are expected to include both PCI and PCI Express bus slots, phasing out the PCI slots during the next year or two.

Another major foreseen benefit is the possibility of increasing to full-duplex GbE and 10GbE, which has not been possible with PCI-enabled boxes.

The bus architecture is also designed for high-performance RAID on the motherboard, with SCSI, SATA (Serial ATA), and Fibre Channel for servers expected when the Lindenhurst chip set is unveiled this fall.

On the notebook side, PCI Express is already creating possibilities.

Nvidia, a designer of graphics chips, said last week that it has support from major notebook manufacturers for its MXM graphics standard for add-on modules that will use the PCI Express bus.

PCI Express-based notebooks should also start appearing this fall, according to Bill Henry, director of mobile product management at Nvidia.

Until now, upgrading graphics on a notebook was not an option. With graphics upgradeability, there is now one less reason to buy a desktop PC, according to Rob Enderle, analyst at Enderle Group.

A single standard for graphics modules will also allow manufacturers to offer more choices in graphics performance without having to redesign the motherboard, which can be used as a competitive differentiator.

According to Nathan Brookwood, principal analyst at Insight64, PCI Express will also give IT managers more flexibility when ordering notebooks and desktops. Whereas the PCI bus requires users to open the box and insert a card, PCI Express will allow manufacturers to put connectors on the motherboard that enable users to simply plug in cables at the back of the box.

On the downside, old expansion cards will not work, and on notebooks, it appears most of the manufacturers will offer a PCI Express Card slot in place of a PC Card slot, requiring entirely new cards.