I know this is probably a really simple thing, and perhaps you have seen this video on Youtube many times. www.youtube.com/watch?v=KUm62292HxY But simply putting these 2 lines of code into Terminal and restarting Safari has made it 10x faster. It's even faster and snappier than Google Chrome on my machine! No more lagging, no more beachballing, it's just constantly fast! defaults write com.apple.Safari WebKitResourceTimedLayoutDelay 0.0001 defaults write com.apple.Safari WebKitInitialTimedLayoutDelay 0.25 Unbelievable!