Go to Safari > Preferences > Security
Deselect: Allow all other plug-ins
Quit and relaunch Safari to test.
If that made a difference, follow the instructions for troubleshooting plugins here.
If it's not a plug ins issue, select the Extensions tab from the Safari > Preferences.
If there are any installed, turn that OFF, quit and relaunch Safari to test. If that helped, uninstall one extension at a time then test.
If nothing above helped, quit Safari then open the Finder. From the Finder menu bar click Go > Go to Folder
Type or copy paste the following:
Click Go then move the Cache.db file to the Trash.