Hello and Welcome to OCN!!
Sounds like you are only using the Auto settings in bios/uefi. You may want to read up on and get to know what and how to do.
Decent overview of your UEFI if you aren't familiar with manual overclocking it can give you a brief glimpse to know what is what.
Here is some decent info about FX 8320E overclocking. http://www.anandtech.com/show/8864/amd-fx-8320e-cpu-review-the-other-95w-vishera/2
Hope some of that helps and you get your 4GHz.