Intel has again pre-empted AMD by launching two new Xeon quad-core server processors, the X5365 and the L5335, ahead of its rival's much-anticipated quad-core Opterons codenamed Barcelona.

And, rubbing salt into the wound, it announced that the X5265 will clock 3GHz compared with the maximum 2GHz of Barcelona, which was originally set for launch this month but will now ship in the first two weeks of September.

The X5265 is also said to be the first of its class to fit a 120-watt power envelope – that is a system with a thermal design that can cope with a processor with that peak dissipation.

AMD has recently shifted the emphasis of its promotion of Barcelona from performance to power efficiency, a factor which for a variety of reasons has become much more important in server farms.

But Intel has pre-empted it on this front too: the new L5335 clocks 2GHz but has a 50-watt power envelope – just 12.5 watts per core.

Barcelona could still prove to be more efficient because it is true quad-core rather than two dual cores in a single module, like the Intels.

Both the Intel processors use a 1333MHz front-side bus and are drop-in compatible with some existing server motherboards. The X5365 will cost $1172 (£576) in bulk and the L5335 $380 (£187).