Since upgrading to 10.8.1 (or around that time), I have been experiencing occasional major lag on my MBP (with 8GB of RAM). I'll just be using it with a few applications open and suddenly everything will begin to lag a lot. At first I thought that it might be a Spotlight issue, as it seems that every time it happens, if I go to check, Spotlight is indexing. Also, I have the console messages mentioned at http://forums.macrumors.com/showthread.php?t=1446854. I tried deleting /System/Library/LaunchAgents/com.apple.afpstat.plist and /Library/Cache/com.apple.coresymbolicationd as suggested at https://discussions.apple.com/thread/4313832?start=0&tstart=0, but if it made any difference, it was only temporary. I have iStats running in my menu bar and it never reports high CPU usage and shows lots of free memory (iStats combines free and inactive memory in the menu bar.) However, if I open Activity Monitor, I find that Safari Web Content is consuming around 5 or 6 GB of real memory with only a few tabs open and that I have only a few MB of free memory. I have three questions: How I can fix my problem? Why does Safari Web Content use so much memory? Even with only Top Sites open, it uses over 300 MB. Why is only my free memory being used up and not my inactive memory? Any help is greatly appreciated. Thanks!