One of the legends of the ppc development game, Chainfire, has released GfxBoost v0.5, this app activates QTV mode which improves speed/smoothness of certain apps, including Direct3D. The app actually slows down FPS but the manner in which it does it makes the screen seem more responsive. Its a bit complicated but it you want to try to boost the responsiveness of your PPC then give it a go. We’ve been playing around with it most of the day and it seems to have few if any bad effects, installation is a breeze and it can be uninstalled.
(per Chainfire and our own experience)
UPDATE: Version .6 released April 28 to add app to programs list and sign the app. Also, positive effects have been noted in more applications