Intel's upcoming 65nm, dual-core Xeon DP processor, 'Dempsey', is fast, but its performance comes at the cost of some serious power consumption, a pre-production test using the chip giant's 'Bensley' platform has shown.

The trial was conducted by website Anandtech, which immediately went off and ran the same benchmarks and power consumption measurements on a comparably configured Opteron 280-based rig.

According to the site's report, the 3.46GHz Dempsey, allied with Intel's 'Blackford' chipset, which supports the dual-core CPU's twin, independent 1066MHz frontside buses, was the clear performance leader, beating the Opteron in both the SQL and order-entry stress tests by 15.9 per cent and three per cent, respectively.

When it came to power consumption, however, the Opteron took the lead, gobbling up 34 per cent, 40.9 per cent and 44.7 per cent less power, respectively, under idle, mid-range and maximum load configurations.

Intel is particularly keen on discussing performance per Watt these days, but it's not likely to include Dempsey in the conversation, at least not if Anandtech's results are anything to go by. Such is the Opteron 280's lead in overall power consumption that despite offering less raw performance than the Xeon, it takes the performance-per-watt crown too.

To see how that might matter to an IT manager, the report calculates that it costs $8,160 more to run the pre-production Bensley-based system - comprising 40 servers - than a similar Opteron rig each year, based on the test results. ®