I have had this problem twice now, first time was with my MB, I called Apple tech support, they didn't really know how to fix it, they told me to switch to a different account, then I was told that apple know about the problem and it would be fixed in 10.5.3. Now I have 10.5.5, I on a brand new aluminum MBP, and am getting this problem again, there is a processes called ATSServer in activity monitor, that is running about 50% of my CPU, also MDS was running about 35%, but, I turned off spotlight, by un-checking all the things that it indexes, and my CPU went back to normal, why does it do that, and what exactly is ATSServer, MDS, and MDWorker (that was acting up last time I had this problem), apple tech don't know what these processes do, you can't end the processes them, they just come back? Also, I have 4 GB RAM, and all I have open right now is safari with 8 tabs, NetBeans IDE, activity monitor, mail, and of course finder, and it says I only have about 400 MB of RAM free. Why is this little bit of software using 3.6 GB of RAM, also if you add up all the real memory, I equals maybe 2 GB, what's going on? Also the integrated GPU is eating some of it, I forgot about that.