Last week I wrote about the poor performance of Windows Vista under the VMware Workstation and Microsoft Virtual PC environments. I noted that Vista was slower than it should be under virtualization, almost as if something - a poorly written kernel driver or bug in the scheduler - was dragging the OS down during benchmark testing. Since my original tests were isolated to virtual machines running atop a Windows H Last week I wrote about the poor performance of Windows Vista under the VMware Workstation and Microsoft Virtual PC environments. I noted that Vista was slower than it should be under virtualization, almost as if something – a poorly written kernel driver or bug in the scheduler – was dragging the OS down during benchmark testing.Since my original tests were isolated to virtual machines running atop a Windows Host OS (Vista 64-bit), I decided to shake things up a bit and repeat the scenarios using VMware Workstation 6.0 running on Ubuntu 7.04 “Feisty Fawn.” The results only served to deepen the mystery.As with Vista under Windows-based VMware, the Vista-on-Ubuntu VM was slower than it should have been. But whereas the former configuration was as much as 50% slower than its equivalent native performance delta – as measured between Windows XP and Vista on bare hardware – indicated it should be, the Vista-on-Ubuntu scenario showed a 93% slower result. In other words, if the delta between XP and Vista running natively is ~2x, and the delta for the same OS configurations under Windows-hosted virtualization is ~2.5x, then the delta under Ubuntu is ~3x. All things being equal, the deltas between these test scenarios – non-virtualized Windows XP vs. Vista on hardware, virtualized XP vs. virtualized Vista on Windows, and virtualized XP vs. virtualized Vista on Ubuntu – should be identical. However, in each case some mitigating factor is causing Vista to run more slowly, as measured by the completion times for the OfficeBench test script, than I would have expected it to give my experience benchmarking the OS natively. And this factor seems to have an even greater impact when running atop a Linux-derived Host OS.Frankly, this is the opposite of what I expected when I set out to repeat the tests under “Feisty.” I figured that the lower overall footprint of Linux – i.e. the whole “runs well on older systems with limited RAM” claim – would have contributed to a better showing across the board. In fact, the opposite now seems to be the case: When it comes to the performance of virtualized Windows XP and Vista, Microsoft’s newest OS mops the floor with Linux…or at least with the Ubuntu distribution of Debian. Go figure! Software DevelopmentSmall and Medium Business