Random large framerate drops on Plains

[BraveDude8]

Specs;

R7 1700 clocked at 3.7ghz
16GB RAM
290x
Game installed on an SSD.

In a nutshell, my game randomly drops to below 40fps on the Plains for no reason. It isn't signified by a giant spike on usage either, so I'm not entirely sure what's causing it. Is this a known issue?

I've done all the basic troubleshooting like verifying/optimising/reinstalling, I've DDU'd and reinstalled drivers, no change.

[ProfessorMeeseeks]

Getting ridiculous frame rate drops too. didnt have this issue before they did the optimize cachce BS. I used to be able to play near max settings, now i cant even hardly play on medium. 

I5 3.2ghz

GTX 460

8GB DDR3

I am fully aware i have older hardware, but i could maintain 40-60fps in the plains 2 weeks ago, and now i cant even maintain 20 at absolute most. I could be standing looking at the ground and be stuck with 13fps. Or look straight ahead for 12-16fps.