I have a 9800 Pro, and with ATi having finally released drivers that work with XOrg 6.8.1, although a little trying to get them working, and being overly sensitive to a kernel recompile, I've still been able to get 3D games going.
In terms of 3D gaming, I've only been trying out the 'native' games so far.[list=1][*]Doom 3 - Works, but not sure about the performance. Some playing around there needed.[*]Unreal Tournament - No problems[*]Unreal Tournament 2003 - No problems[/list=1]
I haven't yet tried any Windows only 3D games through Wine. Although I suspect OpenGL games will probably come out better than the Direct3D ones.
To get the drivers working, the following is just a quick summary of what you need to do (the specific details are explained in half a dozen other ATi driver threads)
(These instructions are for 10.0 or above running Xorg with the 2.6.10 kernel. Where this differs with an older kernel, or 9.1 with XFree86 I'll try to point out.)[list=1][*]Follow the instructions on ATi's website to set up POSIX shared memory in fstab[*]Download the drivers[*]rpm2tgz[*]/sbin/installpkg the new tgz package[*](If running the 2.6.10 kernel you will need to patch the drivers -
http://www.rage3d.com/board/showthread.php?t=33798874)[*]Follow ATi's instructions for manual installation to build and test the fglrx driver module.[*]Run /usr/X11R6/bin/fglrxconfig. This creates an XF86Config-4 file in your /etc/X11/ directory.[*]In /etc/X11, either rename XF86Config-4 to xorg.conf/XF86Config, or copy the relevant details from XF86Config-4 to xorg.conf/XFree86 (all the bits about the fglrx driver basically, and then edit your config so that it uses fglrx instead of the 'radeon' driver with XOrg/XFree86)[*]Restart X and then run /usr/X11R6/bin/fglrxinfo to make sure you are now running the ATi drivers and *not* Mesa3D.[*]Enjoy[/list=1]