First of all, Download AMD overdrive software.... It is the overclocking software by AMD but don't overclock by any software. Download the AMD OD, it will give information about the frequency used by all cores. ... Watch your temps in AMD OD, it will give thermal margin of remaining temps to overheat.... When all done, try to give maximum load to your cpu by any game like battlefield 4, COD ghost or rendering some videos and anything which may give load on CPU and check your frequency and temps in AMD OD. If the frequency didn't jump to 1.4 GHz, then uninstall the previous prime95 and download a newer one.
Sometimes cpu need lesser power even in the test by prime95. .. can you tell me which PSU and GPU you are using?