IBM claims that its server is more cost-effective than the Unisys ES7000 - dubbed the "Intel mainframe". In return, Unisys has pointed out that its latest model offers greater flexibility and scalability.
At Cebit last month, the Unisys ES7000/200 provided a working example of the ability of the company's implementation of the Cellular Multiprocessing environment (CMP) to run 32-bit and 64-bit chips in various combinations in the same cabinet.
Meanwhile, the IBM x440 was shown with a full complement of 16 Xeons, with hyperthreading enabled, running in a Non-Uniform Memory Access (Numa) configuration so that the system monitor saw it as a 32-processor system.
With performance testing pending, it will be a close call as to which scaling method will prove the most economical in terms of overall price/ performance and cost of ownership, but IBM has the upper hand when it comes to initial hardware costs.
The launch of the Unisys ES7000/200 illustrates the battle that is emerging between the clustered environment versus the resilient server. This echoes the battle 10 years ago between Digital's clustered Vax servers and standalone mainframes from competitors such as IBM and Unisys.
The cluster relies on community support, so a server that fails is supported by its peers in the cluster, whereas the single server relies on internal multiprocessor redundancy and self-diagnostics to ensure that uptime is maximised.
A constant competitor in this field is Stratus, which has been quietly selling its Fault Tolerant servers for the past 21 years and recently added an Intel-based ftServer range to complement its PA-Risc Continuum servers.
Nick Cheetham, UK managing director at Stratus, said, "Our ftServers are based on Intel processors but we don't believe that the customer really needs clustering when we can offer a server that is so reliable.
"Clusters are based on the notion that a system will fail. They do allow cheaper servers to be used but in a costly combination of hardware and software."
Stratus argues that its servers may seem expensive but are still price-competitive with a clustered system and are easier to maintain.
The lines are being drawn between the two approaches and it looks likely that there will be a battle between the architectures. The only winner at the moment is Microsoft, whose Windows 2000 Datacenter software is the common link between the "Intel mainframes".
As the number of systems supporting Datacenter increase and companies such as Unisys, Stratus and IBM gain certification, the credibility of Microsoft's bid to add the datacentre to its list of conquests gains ground.