hi ed,
i can't really help you with your graphics problems ... i think, you should try some fedora forums ....
And the performance - I get 75% CPU usage for something I have seen take 48% on a 2.4GHz P4. I have read something on the net about using ICC (Intel's version of gcc) rather than the standard one. Is this what you do?
well, i've been experimenting with icc lately ... this does give a better performance, but it's not 100% gcc compatible. to figure out the performance problem, the way to go would be to use a profiler (like oprofile). i'd also recommend to use devel, since the vectorized versions of the basic dsp functions are between 2 and 5 times faster than the compiler-generated, but it depends on your patch, how much you will gain.
oh well, and if the rendering is done by the software instead of the hardware, this will also make a difference ...
hth ... tim