I am upgrading my Beige 266 G3 Desktop, I dont know which CPU to get. The Sonnet Encore/ZIF G4/500MHz w/1024k 2:1 Backside Cache, or the PowerLogix PowerForce G3/900MHz ZIF with 512K L2 On-Chip Cache. The G4 is only $199 and the G3 is $247. What would be the best buy, pros and cons?