OK... so i got my new iMac today, 27" 3.1GHz i5 Model which i bumped up to 12gb RAM. The first few hours i was using it it was FLYING. Lightning fast. every application was running smoothly, nothing was freezing, pausing, getting stuck, etc... then as the night went on i noticed things were randomly getting stuck or pausing temporarily. it keeps getting worse and now the iMac feels like my 5 year old machine! switching from program to program, i get delays, color wheel pops up a lot, it pauses, gets stuck, etc.. i opened up Activity Monitor and: can someone explain?? I'm running all the exact same programs i had on my old iMac, and that machine only had 2gb of RAM. Maybe Im just reading this wrong. Am I supposed to be looking at USED? or Active?