Back in December we looked at the initial Ubuntu 8.04 Alpha 2 performance by comparing it to Ubuntu 7.10. In that article we had found the performance between the two releases to be roughly the same. Now that we're nearing an end in this development cycle as Ubuntu 8.04 LTS (Hardy Heron) will be released later this month, we've ran a new set of benchmarks comparing the latest Ubuntu 8.04 packages to the previous Gutsy Gibbon release.
It is basically impossible to gain more benchmark speed with an os upgrade. You can only "feel" it faster when some newer kernel options are used. But those are not visable in your benchmark. What I dislike a bit about the latest Ubuntu releases is that there is no live option to disable compiz. You have to use vesa mode if you don't want it. Compiz is not always fun, it adds some effects (which are very restricted in default settings) but video playback does not really work optimal. I prefer such kind of eye candy optional - 7.10 was even fully unusable due to a bug in mesa for my X700SE, now there is a patch in mesa which fixes this problem.
If compiz "cannot" be disabled, then it is a major flaw for me. On my system (F8), it makes the nvidia proprietary driver somewhat unstable in demanding situations, and it decreases gaming performance. So it is useful to be able to disable it.
(of course, with Fedora 9, out of the box Compiz support is very bad: the ugly Fedora "desktop effects" box is still there)
It amazes me how useless the phoronix benchmarks usually are. I can tell you from my years of linux on the desktop usage that hardy will be a big upgrade for responsiveness and interactivity because of the new CFS scheduler. There is benchmarks for that kind of thing too, but they are just as dull. Basically multitasking is much improved. This is something most people that are power users or people that use computers daily for desktop stuff can notice quickly.