the drivers I'm using right now are ATI Catalyst™ 8.6 Proprietary Linux x86 Display Driver.
Well I took it off my workbench, hooked it up to the tv and all was going well till I tried to play a video and got terrible lagg again. Just sitting in recorded programs uses ~20% cpu (16% is mythfrontend) then as soon as I open a video X jumps to 86%.
fglrxinfo at xterm
display: :0.0 screen: 0
OpenGL vendor string: ATI Technologies Inc.
OpenGL renderer string: ATI RADEON 9600 Series
OpenGL version string: 2.1.7659 Release
glxinfo | grep direct
direct rendering: Yes
rpm -qa | grep fglrx
remember this was working perfectly on md4, and transfers across the wired network at ~11MB.