While the FFmpeg encoding performance was unaffected by the different virtualized Ubuntu guests, the x264 H.264 video encoding performance improved with Ubuntu 10.04.1 LTS and those gains are still present in Ubuntu 10.10.
The 7-Zip compression performance has also been on the rise since Ubuntu 8.10, but may have slightly receded when compared to this year's Long-Term Support release.
Looking at how the performance of Ubuntu Linux has changed since early 2008 in a virtualized environment proved to be interesting, but the results are not too surprising when compared to what we experience when running this Linux distribution on real hardware. To sum it up, there are some disk performance improvements when switching from the EXT3 to EXT4 file-system, but some of those gains have been erased in more recent versions of the Linux kernel as the EXT4 file-system has been made more reliable. Besides the disk changes, there's some other performance improvements made between Ubuntu 8.04 and 10.10 that can be found when using the TTSIOD CPU-based renderer, x264 video encoding, and 7-Zip compression, from the test profiles we ran across these six virtualized Ubuntu releases. The only test where Ubuntu 10.10 was measurably slower than the one and two-year-old Ubuntu releases was with the C-Ray ray-tracing renderer.
If you are interested in more virtualized Linux benchmarks, let us know!