Unfortunately I dont think there is much you can do but tweak a few settings. I play planetside 2 as well, and that game just isn't optimized as well as it needs to be. The game is very CPU intensive, and no matter what CPU you use, you are going to experience some FPS issues. In fact, i'm surprised you're able to run it decently on ultra!
I think changing the Shadow settings will have the best impact. Low and Medium Shadow settings don't look too bad, and it may be worth keeping it on the setting you have now and lowering it when you start to enter the bigger battles. I change it to the highest setting when I'm casually working on a Hive where there isnt a battle, then change it to off, low or medium when battling.
in fact, changing it to OFF has the best impact. It really doubles your FPS! Sadly there arent many shadows, but honestly man, you get used to it pretty quickly. With your specs, i think LOW will actually be a big impact as well.
Tips to improve FPS:
-Lower Shadow settings during big battles. (OFF has a HUGE impact!)
-Avoid BioLabs (if you enter one, try low shadows. if that doesnt help, turn them off)
-Lower render distance slightly.
In conclusion, Planetside 2 is just a disaster for even high end PCs. You think you have the hardware to run ANYTHING, but then Planetside 2 comes around and says "lol nope, heres some.....UNOPTIMIZED SHADOWS!"
Hope that helps. It sucks to have such high end hardware and still struggle with games. But its not your fault. Planetside 2 is poorly optimized.