Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
Ubuntu 9.04 (the Jaunty Jackalope) will be released towards the end of next month and it is picking up the Linux 2.6.28 kernel, GNOME 2.26, and other improvements like install-time support for the EXT4 file-system and some subtle improvements.
When it comes to the X.Org side it is shipping with X Server 1.6 and the stabilized version of Mesa 7.3. Specifically in regards to the ATI Linux graphics, it will be shipping with an updated xf86-video-ati driver by default and Catalyst 9.4 will be an option for the user (in fact, right now Ubuntu 9.04 is using an unreleased driver). With Ubuntu 9.04 Alpha 6 having been released last week, we have run a few benchmarks comparing the open-source ATI performance in Ubuntu 8.10 and Ubuntu 9.04 Alpha 6.
With Ubuntu 9.04, the out-of-the-box ATI experience is great with the R100 through R500 series, complete with 3D support. Ubuntu 9.04 also has X-Video and EXA support for the ATI R600 (Radeon HD 2000/3000) and R700 (Radeon HD 4000) series through a recently-updated DDX driver and updated kernel DRM. While Intel's open-source driver has picked up DRI2 support, kernel memory management (via the Graphics Execution Manager), and numerous other improvements as of late, none of these features can be found in Jaunty's open-source ATI stack since they are still very much under development.