If I'm not otherwise engaged next Thursday morning, I just might spend my economic stimulus check to enter the PC server business. I could go shopping for a wholesale 1U bare-bones rack server, with my primary criteria being that it boot DOS from a floppy and require you to take your server off-line to change basic system settings. I'll stuff that two-socket black box with RAM, CPUs, and disks; charge you for your choice of Windows or Linux; and unless you're buying these things by the gross, stick you with desktop-grade support. Since I had no involvement in your server's design and engineering, I'll rely on BIOS and driver updates from my volume motherboard supplier. I'll selectively pass these on to you, flagged with warnings about how they may render your system unusable if you misapply them, until my supplier stops issuing them. Don't worry, you'll have a solid year before that happens.
This would be a ridiculous way to open a review of Apple's latest Xserve if it didn't describe a sub-US$5,000 PC server so well, as well as everything that Apple neglected to design into its eight-core, 1U Unix rack server. While Apple's latest Xserve uses the Intel Harpertown quad-core, Core 2 Xeon CPU, it is in all other regards the glorious antithesis of a PC server. With Xserve, Apple designed and engineered everything in-house, from the logic and firmware to the chassis and OS and admin tools. Support issues are not finger-pointed out to Microsoft, Novell, Red Hat, or GNU. Like your feature requests, your support tickets can land on the desks of the engineers who created what you're using. Xserve is built and supported to run not for one or two years, but three years, five years, and beyond. If you think I'm having you on, try to find a bargain Xserve on the refurbished market.
You expect the best of everything when you buy a proprietary big iron Unix server from IBM, HP, or Sun with a base of $20,000. If you want big iron Unix server features from a 1U x86 rack server with an entry price around US$3,000, or $5,000 with eight 64-bit processor cores, you take your business to Apple. And unlike the big iron Unix servers, Xserve can consolidate your Windows, Linux, and even OS X servers through Parallels or VMware virtualization. Xserve extends its standard benefits of online and lights-out remote GUI (or command line) management and the rich services of the bundled OS X Leopard Server (true, certified Unix) to all applications and OSes the Xserve hosts. (See "Leopard Server: The people's Unix.")
No forks in the road
Consistency and continuity are hallmarks of Apple designs. The eight-core Harpertown Xserve is, at heart, the quad-core Xeon Xserve system that I detail in my review of the first Intel-based Xserve. The Harpertown model is significantly enhanced but not reworked. If you have a four-core Xserve, you don't need to replace it to stay current with the vendor's latest technology. Apple's free, automatic software and firmware updates make four- and eight-core Xeon Xserves functionally identical. For that matter, dual- and quad-core (two-socket) PowerPC G4 and G5 Xserves run the same Leopard Server OS and are managed the same way, albeit without Xeon Xserve's lights-out and x86 guest OS capability.
As Intel worked it, Apple could have made the transition from a four-core server (two cores by two sockets) to eight cores by doing nothing but a chip swap, but Apple didn't settle for a mere processor upgrade. Apple's original Intel Xserve design was built to embrace evolution while keeping the price either flat or on a downward curve relative to prior generations. Brilliant reuse of design elements results in lower design and manufacturing costs for each generation of Xserve, but instead of taking the lower cost as a windfall, Apple shares it with buyers in the form of upgraded standard features.