"This has happened because of two changes and a lack of
co-ordination between ATI and Linux developers. The first change is
that many desktop Linuxes, including Ubuntu 9.04 and Mandriva 2009
Spring are now using the latest X.Server, version 1.6.. X.Server
provides the basic framework, or primitives, that Linux and Unix
computers use to display their graphics. Everything else you think
of as the Linux desktop, such as GNOME 2.26 and KDE 4.2.2, runs on
top of X.Server.
"X.Server 1.6 has been available since February of this year.
ATI didn't support it immediately. And, this is where the second
change came in. The graphics branch of AMD finally got around to
supporting X.Server 1.6 with the ATI Catalyst 9.4 driver (aka fglrx
9.4) release in late March. There's only one problem with these new
drivers: They don't work worth a darn."