I use this CPU in a motherboard, does not officialy supporting top FX series. Also, my ram is running on low mhz. Only 1700. Cinebench and render software's are preferring high ram settings.Note to siriq...
Your 4.8 overclock doesn't seem optimal after all. I guess I mistook your SIMD results for your stock Blender results or something because your Blender results are lower than my Piledriver results as is your Cinebench multi. In fact, I was able to get 770 as a new high with Cinebench multi at 4.8 (up from two runs at 767).
Using the formula with your SIMD result gets only this score: 37314. Mine was 45455 at 4.8.
With the stock build the result is only 20000. Something is off with your system. Must be throttling.
You said 2:05 (125 seconds) for stock Blender at 150 samples. That's 96000000/125/8/4.8 = 20000. By contrast, I got 23923.44