Is my CPU causing a bottleneck?

[Calvinb81]

Specs:

i5 2500k @ 4.4GHz
MSI GTX 970 4GB
8GB DDR3 Ram @ 1333Mhz

I have looked on a lot of threads online and they all say that the i5 2500k overclocked would not bottleneck the 970. But after playing battlefield I'm looking at my CPU to GPU usage and I was dropping to 40-50 frames when my GPU usage was at 60-70% and my CPU was at 100%.

So am I correct in thinking that these threads were wrong and my CPU is bottlenecking my GPU?

 

[Calvinb81]

i5 2500K is still offering high end gaming performance. OCed you are running with the best of the best. http://www.tomshardware.com/reviews/gaming-cpu-review-overclock,3106-5.html

But then why is my CPU usage maxing out at 100% on Battlefield 4 of all games when my GPU is only at 60-70%?