Try lowering your settings. My problem is on Octane where I'll often hit 40~50 FPS drops and I'm using pathetically low settings on an i7-3930K with SLI GTX 770's rig; my settings - http://i.imgur.com/SdCHK2F.jpg The vRAM could be playing a role, my GPU's only have 2GB (optional 4GB oopsy) and the GTX 780's 3GB vRAM. I'm assuming you're running a gun with a dual rendering scope and after the past couple of 'updates' I'm often enough getting FPS drops on a few maps. I have noticed that my details have increased without changing my settings...
I do recall a some frame drops around the crash site on Stonehaven, but Octane for me and without a 'scope' (reflex/red dot) is the most annoying.
Regardless the last couple of 'patches' weren't a step forward, and about the only 'good' thing was access to my BO2 MP background ... yippee.