My PC :
i7 5930K @ 4.6 GHz (6 cores, 12 threads)
980 Ti (Gigabyte G1 Gaming) @ 1450 MHz
16 GB DDR4 Quad channel
1440p 144Hz GSync monitor
Everything set to Ultra, 60 FPS cap, MSAA 4x, 1440p.
I'm getting 60 FPS in the Outback but 55 in the first city and 45 in Surfers Paradise, in the cities the first core is always at 100% and the last four are not even used.
If my screen is set to another HZ than 60 I get awful stutter.
Also, I just disable Hyper Threading and now I get way more FPS, I'm getting 55-60 in Surfers Paradise and less core 1 usage
So i7 users, turn off HT for this game until it's fixed :/