I recently picked up a copy of PPC Tiger and I instaleld it on my old iMac G3. The system is a little bit more responsive thanks to the new system. It has 640 MB of ram installed (I know I could put 1GB, but 30$ for a 512MB stick seems very expensive to me), and has a 400 MHz G3. Right now it has Firefox 2.5 on it (because it's the last supported version under 10.2.8, its older system). I hesitate to install Firefox 3.5 because I fear it would be even more sluggish. I know it's less of a memory hog than Firefox 2.5, but what about CPU consumption? Anyone has tried it on at least a G4, or better a G3? Was it worse or better?