I started having this same problem after the last update.
I'd doubt it's a bottleneck problem cause on my i5 4570 I get arround 60%-70% cpu usage (with a gtx 1070 as well).
And only if it gets too crazy I get just 1 of the cores above 80%, and still doesn't reach the 90% cpu usage...
Plus I gotta mention that before the last update I didn't have this problem at all. Game performed fine.
So I do believe is the Squad optimisation...
I've read a couple of guys saying that turning off the HPET or the EIST like Virtualevil said helps.
So I'm gonna try that and see how it goes.