I had this same problem, too, even though my specs exceed even the recommended. Finally bought an SSD today and the game runs much better but it’s still a bit laggy even on an SSD.
Specs:
CPU: Intel Core i7 4790 @ 3.60GHz
RAM: 16.0GB Dual-Channel DDR3 @ 799MHz
GPU: 2047MB NVIDIA GeForce GTX 1060 6GB (EVGA)