i5 3570k Bottlenecking my GTX 970?

Nitro192

Distinguished
So, I recently picked up a Gigabyte GTX 970. Love the card to death, it's a dream come true after coming from a 2GB 770. Major performance jump imo. But there's one game that evades me. Assassins Creed Unity. I can maintain constant 60fps in the entire game except for the one scene in front of the huge Church (Which btw, that church is probably the most massive, highly detailed building i've ever seen in a video game) but anyway. It seems my CPU spikes to 100 during this section.

My i5 3570k is Overclocked to 4.3Ghz. So is it possible that it might be causing a bottleneck on the 970? I have Unity on a 240GB OCZ Arc 100 SSD so hard drive isn't the problem. 8GB Corsair vengeance Ram so that isn't the issue. The only low quality part on my entire build is my Corsair CX600 PSU. So I'm wondering if that's the issue.

I've been dealing with CPUs a long while and up until today was convinced the 3570k at 4.3Ghz would never be a bottleneck. Even GTAV on Ultra, it never goes above 70%. So was I mistaken? What could be causing this. Any thoughts on this matter would be appreciated.