Going with VMware has several advantages, says Krishnamurti. Users can create Vista virtual machines for either 32- or 64-bit CPUs, and those with multicore PCs can allocate up to two CPUs worth of processing power to a single virtual machine. VMware also lets users create a Vista virtual machine once and run it on different PCs without tweaking. Finally, Krishnamurti claims that VMware, as the veteran in the marketplace, handles device drivers very well. "We've tested this pretty extensively," he said. "But if you plug in some random USB device, and it doesn't work, we want to know about it."

Krishnamurti does admit that the latest official versions of its Server and Player products only support USB 1.1, though beta versions out now do offer USB 2.0 support. Those updates will be released officially by the first half of next year, probably after Vista's Jan. 30 launch to consumers.

Parallels Workstation: Fast and furious

Another offering is Parallels Workstation for Windows & Linux from Parallels Inc. The Renton, Wash.-based firm made a splash earlier this year when Workstation's sister product for the Mac was the first to allow Intel Mac owners to run Windows simultaneously with OS X. (VMware has subsequently released a similar product, while Apple's Boot Camp lets users run either Windows or OS X, but not both at the same time.)

Parallels announced last week that the latest update to Workstation, Version 2.2, will run Vista virtual machines. Workstation 2.2, which leverages virtualization technology built into newer AMD and Intel processors for faster performance, will be able to run Vista Ultimate and Vista Business, which cost US$399 and $299, respectively.