I am wondering if my experience is normal, and within expected performance guidelines. I started with a blank Logic Pro document and put four instances of GPO on 4 tracks (two solo dry violins, 1 dry solo viola, and 1 dry solo cello - all MONO). I go to play, and Logic crashes immediately before a note is heard. This happened over and over again half a dozen times. I repaired permissions, I tried freezing tracks, etc. I finally gave up on GPO, and put four instances of stereo Absynth 3, and it worked fine with no crashes.
My system : Powermac G5 dual 1.8 with 4 GB ram. System 10.4.6, Logic Pro 7.1
As an aside, but still on the subject of the type of audio instrument type you select in Logic for GPO... I've discovered that if you want to use more than one instance of GPO in Logic, you shouldn't mix instances of stereo and 'multi' audio instrument types. See this thread: