The company announced five models, each with two processor sockets, and promised a significant performance increase over those systems with the dual-core Xeon 5100 "Woodcrest" processors. In the case of the x3650, an integer-processing speed test yielded 64 percent better performance with the quad-core processors than with dual-core, IBM said.
IBM will begin taking orders for the quad-core systems on Tuesday, but volume shipments won't begin until December for the x3650 and a slimmer sibling, the x3550, IBM said. The other models will become generally available in January.
Dell began selling its quad-core servers Wednesday.
Quad-core processors have four processing engines; Intel's Xeon 5300 consist of two Woodcrest chips in a single package. Intel rival Advanced Micro Devices prefers to put all four cores on a single slice of silicon, but its first quad-core Opteron chips, code-named Barcelona, won't arrive until mid-2007.
Earlier this year, Intel introduced its "Bensley" dual-processor server platform, which combines various processors with an Intel chipset. Bensley-based systems can be upgraded with the Clovertown chips, though using high-end chips will mean an increase in both electrical power consumption and waste heat compared with Woodcrest.
Future dual-core and quad-core chips built with an upcoming 45-nanometer manufacturing process will also plug into Bensley platforms, Intel has said.
IBM's new servers include the following:
• The x3650, a 3.5-inch-thick rack-mounted machine with a starting price of $2,419.
• The x3550, a 1.75-inch-thick rack-mounted machine with a starting price of $2,369.
• The x3500 and x3400 servers are free-standing tower models with starting prices of $2,189 and $3,049, respectively.
• The HS21 is a blade server with a starting price of $3,049.
