For those having trouble with slow Hypershade scrolling / zooming under OS X 10.5, try and disable your V-Sync to speed things up!
A temporary fix can be found with this App
Install, and follow instructions. The changes to your Windowserver UI is only temporary, and is reset on the next restart. I usually run the Beam sync disable tool before starting Maya. Note this may affect flash movies in your browser...Play around with it first! Hope it helps some!
For those with Geforce cards, add the following lines to your Maya.Env file...
MAYA_SLOW_DRAWPIXELS = 1
This should help speed up ImagePlanes...If it doesn't help you then just remove the lines. Sure speeds up my ImagePlanes!
If you are lucky enough to have a Quadro card in your Mac Pro, then add these lines:
MAYA_ENABLE_HWR_CG_PROGRAMS = 1
MAYA_HWR_CG_FRAGMENT_PROFILE = arbfp1