Not sure about your FPS problem but whatever "dealer" your going with sounds like her is BSing you about "unlocking all 8" of your cores.
7700k is already unlocked
it only has 4 cores and the other 4 aren't quite cores. It's hyperthreading which really isn't another 4 cores.
Yeah , the moment he said that , i knew he was talking about the threads . But still , knowing that hyperthreading is enabled but still the cpu itself is still having a hard time to perform to its full potential is still the main question here .