Details of the new Coherence mode in Parallels desktop version 2.5 were demoed to TMO on Thursday at Macworld by Ben Rudolph, Parallelis Marketing Manager. Briefly, the Coherence feature allows the user to suppress the Windows Desktop and access Windows applications directly, as if they were Mac OS X applications.

The Coherence mode works by initially placing a Windows application in the Mac OS X Dock where it is marked with the small Parallels orange logo to identify it. It is clicked to launch like any other Mac OS X application.

The Parallels Desktop is virtualization software that allows guest OSes to run along side Mac OS X in native mode and at nearly full speed on an Intel Mac.

Mr. Rudolph told TMO that, at first, Parallels was thinking about calling this "Windows without Windows" which leads to an obvious acronym, but they decided on the label Coherence instead. In addition, version 2.5 adds a true Windows native full screen mode requested by users. Another feature added is the dynamic resizing of Windows when running on the Mac OS X desktop. Mr. Rudolph told TMO that Beta 3 appears very stable and recommended that it can be installed and used until the final release arrives. This reporter upgraded without incident.

TMO was told by Mr. Rudolph that each OS runs on its own core in a dual core system. As a result, the optimum number of OSes to run on a dual core Mac is two. However, more OSes can be run with a performance penalty.

Finally, Mr. Rudolph also stated that Parallels plans to introduce accelerated 3-D graphics support in version 3. Version 2.5 remains constrained to the first 8 MB of Macintosh VRAM and can only run Vista in the non-Aero mode.

Parallels Desktop for Mac OS X is priced at US$79.95. The upgrade to version 2.5 is free.