Looking very seriously at buying a used Powermac G4. Have a few looming questions. How do the various L2/L3 cache configurations affect real-world performance in common apps such as movie playback, A/V encoding, and overall system responsiveness? How much does memory bandwidth play a roll in overall system performance? Are most/all Powermac G4s based on 100/133 mhz SDRAM? Has anyone done an exhaustive benchmark comparison between various flavors of G4 at similar (as close as possible) clockspeeds with varying amounts of memory bandwidth, or across different G4 motherboards? (Yikes vs Sawtooth vs Digital Audio vs Quicksilver).