IBM has launched a Linux and Windows server to encourage 64-bit take-up and 'pay-as-you-grow' expansion to complement its 32-bit xSeries systems.

The 64-bit eServer xSeries 455 uses all the features of the Intel Xeon (32-bit) x440 and x445, including high rack-density and IBM's Enterprise X-Architecture (EXA), but has Intel Itanium 2 64-bit processors.

"When the x440 was released [Dec 2001], its EXA architecture was the blueprint for the next five years for high-end servers," Tony John, IBM xSeries brand manager for UK and Ireland, told vnunet.com. "This has now been 90 per cent replicated for 64-bit."

The x455 grows from four to 16 processors in four-processor increments. There is also input-output expansion and a memory maximum of 56GB per processor node.

The vast majority of servers sold use four or less processors, with HP and Dell both reining back eight-way system production through lack of demand.

But John maintained that the x455 was aimed at customers experiencing bottlenecks at the top end of 32-bit environments, for instance those with very large databases or needing a large single instance of the operating system.

Nigel Montgomery, research director at AMR Research, said: "It is good timing for a 64-bit system.

"But I would argue that it is playing catch-up, because IBM's iSeries has had 64-bit for ages. The major thing for xSeries is that it's a sign of parity [with iSeries]."

IBM does not preload the Linux or Windows operating system, and the company's on demand strategy is entirely complementary to pay-as-you-grow, according to John.

"It depends on how you're buying in the first instance. For example, websites such as Wimbledon have peak demand once a year, so might be covered by leasing," he said.

"But a database tends to expand and you don't want to throw anything away."

Montgomery agreed that the x455 was suited to on-demand because it would enable better response to a fluid requirement.

General availability will be from 9 December with prices ranging from £12,500 to £50,000.

IBM has also announced Remote Supervisor Adapter II, available as an upgrade for the 32-bit x445, improving graphics and facilitating remote 'lights-out' control through any web browser.