With its update to Virtual PC 4.0, Connectix continues to improve the company's popular Pentium emulation software in compelling ways. Most important are the performance increases, of course, which reportedly can as much as double Virtual PC 4.0's speed over the previous version, though the trade-off is that Virtual PC now requires a PowerPC G3- or G4-based Mac (including Macs with upgrade cards; Virtual PC 3.0 remains available for older Power Macs). On PowerPC G4-based Macs, Connectix claims that Virtual PC 4.0's use of the Velocity Engine can also improve multimedia performance in MMX-savvy Windows applications by up to three times. Other architectural improvements include internal allocation up to 512 MB of RAM to the emulated operating system inside Virtual PC using temporary memory, and dynamically sized disk images that expand as needed and use only the space required. Conversion of existing disk images from previous versions is possible but requires a multi-step process because of Windows limitations that Connectix plans to document on its Web site. Virtual PC 4.0 also features some interface enhancements, such as resizable, scrollable windows, support for three-button mice and mice with scroll wheels, improved help, and improvements to the Virtual Disk Assistant and Setup Assistant.

<http://www.connectix.com/products/vpc4.html>

Of special interest to people who use Virtual PC to preview Web pages in different Web browsers is Virtual PC 4.0's new capability to run multiple PC operating systems at the same time. You can have two or more PC operating systems active at once, though you may want to have only the frontmost operating system active (leaving the others in a saved state) for optimum performance. In the first quarter of 2001, Connectix will also be releasing Connectix OS Packs that let users buy pre-installed versions of different operating systems.

Virtual PC 4.0 requires a PowerPC G3- or G4-based Mac with at least 50 MB of RAM and Mac OS 8.5 or later, but it is not compatible with Mac OS X Public Beta. Connectix plans to release a compatible version as soon after the final release of Mac OS X 1.0 as is possible. The upgrade from Virtual PC 3.0 costs $79 (free if you purchased Virtual PC 3.0 after 01-Nov-00) for either a physical or downloadable version (about 20 MB - available now). New copies of Virtual PC 4.0 with Windows 98 (shipping 14-Dec-00) or Windows Me (shipping 11-Jan-01) cost $199 on CD-ROM.