Since this is my CPU I'm obliged to help lol.
What's the rest of the rigs specs?
Have you monitored the CPU clock speed in game? It should be around 4Ghz.
What was the fire strike CPU score?
And certain nothing is hogging the system in the background?
GPU: GTX 970
RAM: 2x8GB Corsair LPX DDR4-2400
Mobo: Gigabyte GA-Z270-HD3P ATX Motherboard
SSD: Crucial M4 2.5" 256GB SATA III (the one the game is currently installed on)
Score in Fire Strike after just leaving The Witcher 3: 9870
Score when I tried it earlier in the day: 9868
Example of what the FX-6350 gave me: 8151
Edit: Ah wait, you asked for CPU score, not overall. If you mean the Physics Test, then it scored 12928 and 12715, while the 6350 previously only managed 6736. So in Fire Strike the thing has roughly doubled my result.
Will take a look at CPU clock in game.
Edit:
Okay, having trouble figuring out how to track the CPU clock speed (using MSI afterburner), but did notice something interesting on CPU usage. In Novigrad, which I know is one of the most CPU intensive areas of the game, the 6700k was only hovering around 50% usage on the various cores. Is that where it should be?