After 115106

After 5/10 mins drops 60/55 to 1/8 fps.
But CPU/GPU/RAM used under 50%

CPU: i5 4670k OC @4.2 GHz
GPU: Sapphire 7870Ghz Edition X2 with catalyst 13.12
OS: Win7 64
MB: MSI Z87-G45
RAM: 16 GB Corsair Vengeance 12800
SSD: Hyper X 3K 120 (OS & game)