IBM will upgrade two high-end System p5 servers next month, the System p5 590 and 595 Unix servers.

System director Jeff Howard said IBM planned "to turn up the heat on Unix server competitors, but turn down the heat in the data centre" on the 11 August launch date.

According to Howard, the new servers use the more powerful Power5+ processors (introduced in January) to replace the Power5 chips used in the original models, with performance up by a claimed 20 to 25 percent.

The p5 590 will hold up to 32 Power5+ processor cores running at 2.1GHz and 1TB of memory, while the p5 595 will hold up to 64 Power5+ cores running at up to 2.3GHz and 2TB of memory, making it the company's most powerful server, IBM said.

A top-of-the-range 64-core p5 595 will cost $3.46 million, equipped with 2.3GHz Power5+ processors, 256GB of memory and two 36.4GB disk drives excluding the OS licence - around the same price as the original model with 1.9GHz Power5 processors. At the other end of the scale, an eight-core 2.1GHz p5 590 with 32GB of memory and two 36.4GB disk drives will cost $421,074, the company said.

The Power5+ processor first appeared in low-end System p5 servers last October, but those chips ran slower than the models that will be introduced in August, at 1.9GHz, Howard said. "We started at the low end with the lower frequencies which are easier to manufacture. As you go along, you get the yields you need to support the higher frequencies" needed for high-end servers, he said

Heat dissipation is reduced by new technology, according to IBM. It's using a new production technique it calls "dual stress" to pack different kinds of transistors closer together on the chips. "You get higher performance with better power efficiency," Howard said. Better power efficiency means systems run cooler and so more servers can be packed closer together in the data centre without overheating.

Overall system performance is more important than computing power per square metre of floor space, however, Howard said. When it comes to server consolidation, virtualisation software can play as big a role as packing more processors in a rack. The new systems can support up to 10 virtual servers, or partitions, per processor core - although IBM's management software imposes an upper limit of 254 partitions, he said.

Virtualisation, however, makes it harder for organisations to attribute the cost of hardware to the departments or applications that use it. To simplify that task, IBM will offer a version of its IBM Tivoli Usage and Accounting Manager (ITUAM) for the new System p5 servers. The software is already available for the company's System Z servers, Howard said. Using data already captured by Version 5.3 of IBM's AIX OS, ITUAM can break down charges by cost centre, application, server and so on, he said.