This is a repost of an older blog post, it was something that helped me out of a hole a while back. Maybe it’s still relevant.
I noticed an issue with Safari, when opening a new tab, and beginning to type the address, it would freeze for a few seconds. Not a lot, but enough to be annoying. It would also happen sometimes when switching between tabs, or Safari Windows.
Anyway, after doing some research, I found this:
“Try this: first, go to your Finder: There, go to your User Account>Library>Caches. Move to the trash the com.apple.Safari file and the Bookmarks folder in Caches>Metadata>Safari folder. Next, same library, go to the Safari folder, moving to the trash the History.plist file. Now restart Safari and try the URL window.”
Credit goes to Hawaiian_Starman on Apple Forums, the thread is here: https://discussions.apple.com/thread/1532889