The very first Xeon processors built on Intel's 45-nanometer Penryn architecture have been revealed, according to a leaked memo circulated inside the semiconductor firm. The new chips, already nicknamed "Harpertown," will both represent Intel's first quad-core x86 chips to move beyond the 3GHz barrier while also improving the efficiency of the cores themselves. A top-end Xeon X5640 will peak at 3.16GHz, with at least 2.83GHz (E5440) and 2.5GHz (E5420) chips occupying the mid-range and a low-power 2.33GHz model (L5410) consuming only 50 watts of energy on average. All editions will have 12MB of level 2 cache versus the 8MB of today's CPUs, reducing the likelihood of bus or memory bottlenecks.

Dual-core processors will also be available, the note said. These simpler Xeons, called "Wolfdale," will reportedly have 6MB of cache (upgraded from 4MB) but make up for the lack of extra cores through clock speed and power draw: the 3.33GHz E5250 will consume 65 watts while the L5250 at 3.16GHz will need only 40 watts. Few dual-core CPUs will be available as the multi-core aware programs often run on Xeons will benefit more from four cores versus two, according to one Intel engineer.

Prices for the chips were not part of the leak but are expected to push the overall pricing downwards, making quad-core and faster dual-core processors more readily available. The fastest known Xeon today is the 3GHz X5365 quad-core model used first in the Mac Pro.