Try troubleshooting extensions and third party plug-ins.
From your Safari menu bar click Safari > Preferences then select the Extensions tab. Turn that off if there are any installed. Quit and relaunch Safari to test. If that helped, turn extensions back on then uninstall one a time to test.
If it's not an extensions issue, try troubleshooting third party plug-ins.
Back to Safari > Preferences. This time select the Security tab. Deselect: Allow all other plug-ins. Quit and relaunch Safari to test.
If that made a difference, instructions for troubleshooting plugins here.
Anti virus software installed? MacKeeper?
Remove all items from System Preferences > Users & Groups > Login Items
Same for HD > Library > StartupItems then restart your Mac and try Safari.
If that didn't help, open a Finder window. 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.
Quit and relaunch Safari to test.
message edited by: cs