.....
i've answered this again, and again...but here goes....
on Linux, the GPU does NOT do any accelleration for HD. So a faster CPU is needed.
and NO, the 6200 is not weak.. it's the right size for this system, and the drivers that come with even the current release of 0704 will work out of the box with it. AND you'll get UI2 with Alpha composited blending of the UI..something the commercial ATI drivers STILL can't do correctly...
as I said before... swap out the ATI card for an NVIDIA one, preferrably a 6200.
-Thom