PCI-X marks the spot for IBM, HP

Big-name companies have begun to side with this technology for plugging network cards and other devices into servers.

Stephen Shankland Former Principal Writer
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Stephen Shankland
3 min read
Big-name computing companies have begun speaking out in favor of the PCI-X technology for plugging network cards and other devices into servers.

IBM and Hewlett-Packard will start incorporating PCI-X into their servers in 2004, according the companies' top Intel server technologists. The move will be possible through the use of new chipsets, which join processors to memory and input-output systems such as PCI, from Broadcom subsidiary ServerWorks.

Those companies and others plan to endorse PCI-X technologies in a joint announcement next week. But not everyone is such a big fan.

Dell Computer, the No. 2 seller of Intel servers after HP, prefers a different standard called PCI Express. Dell's strategy dovetails with that of Intel, which is employing PCI Express to connect chips within a server and which, like ServerWorks, builds the chipsets that link processors to other parts of a computer.

PCI is the dominant standard used to plug network adapters and sound cards into computers. A faster version called PCI-X now is used for servers, which have a greater requirement for high-speed networks and other external connections.

Now server makers are focusing on PCI-X 2.0, two versions of which are called PCI-X 266 and PCI-X 533. Those faster successors are needed to keep up with coming versions of networking technology including InfiniBand, Ethernet and Fibre Channel, all of which will be able to transfer 10 gigabits of data per second.

PCI-X is an extension to existing PCI, meaning that older network cards can be used in newer systems, a factor PCI-X advocates say is key in determining future plans.

"An incremental improvement on an incumbent standard is very attractive," said Tom Bradicich, chief technology officer of IBM's xSeries line of Intel servers.

HP agreed. "Full backward compatibility with the millions of installed cards is a real compelling story," added Karl Walker, CTO of HP's Intel server hardware, who believes PCI-X will prevail among customers through 2005.

Dell is embracing PCI Express more swiftly. "We're constantly evaluating all technologies, but for now Dell remains focused on PCI Express as the best choice for our customers," the company said in a statement.

Dell's and Intel's support is important for PCI Express: Their presence will help convince companies with network cards or other adapters to make PCI Express models.

PCI-X 266 likely will arrive about a year from now, with PCI-X 533 coming the year after that, said Kimball Brown, vice president of business development for ServerWorks. Bradicich and Walker agreed with the assessment.

PCI Express requires a different hardware connection, meaning that old PCI cards won't work in PCI Express slots, but it does let companies re-use the same software. Because of some significant design advantages over PCI-X, PCI Express likely will win out in the long run--likely after 2005, after the technology has had some time to mature in less-demanding desktop computers.

PCI-X uses a "parallel" design with wires whose signals must be carefully synchronized, a difficult feat as speeds or wire counts increase. In contrast, PCI Express uses a "serial" design with a small number of independent high-speed wires. Though the initial incarnation of PCI Express will use slide-in cards similar to PCI, the PCI-SIG, which develops and manages various PCI specifications, is contemplating cable and other connection technologies.

One problem for PCI-X is that making it faster requires high quality control in manufacturing that can be expensive, said Gartner Dataquest analyst James Opfer.

The two technologies aren't mutually exclusive, but supporting both in the same machine costs server makers more and uses up valuable internal real estate.