My Samsung Galaxy S3 Neo i9300 became slow and started freezing more frequently.
Based on the post I tried to clear the cache partition as instructed in this video:
Power off phone (hold power button, choose power off).
Press and hold following buttons together: Volume Up, Home, Power.
Hold all buttons until phone vibrates and shows message recovery options.
Release Power button.
Choose wipe cache partition.
Wait until message Cache wipe complete.
Choose reboot system now.
You are done.