IBM eServer xSeries 440

Winner: IBM eServer xSeries 440

It's the server that's almost a mainframe. The IBM eServer xSeries 440, the flagship of the IBM xSeries server line, is a 4U rack-mountable system that houses up to eight Xeon MP processors. This alone puts it at the top of the Intel-based server market. Most high-end machines don't use the Xeon MP, which is built on the same core architecture as the Pentium 4. (They usually use older Xeon chips based on the Pentium III.) But what's most amazing about the 440 is how well it handles system failures and repairs.

Its 64-bit PCI-X slots let you add, remove, and replace adapters and hard drives without disrupting your system's operation. It offers redundant fans and power supplies, which you can also swap in or out while the OS is still running. Thanks to a light-path diagnostics board, you can quickly identify system failures without pulling the machine out of its rack. Technologies known as Chipkill and Memory ProteXion constantly work to prevent, correct, or reroute memory errors.

To top it all off, IBM lets you mirror the system's entire memory subsystem. "We divide the full memory capacity in half and do dual writes," says Jay Bretzmann, director of marketing for IBM's server division. "This allows it to recover from even the most catastrophic memory errors."

Because all this is done with a single memory controller, mirroring doesn't degrade system performance. (IBM Corp.,