integrated graphics

I've got an MSI GP72 2QE with a i7-5700HQ, GTX950 M and 8 GB ram on Windows 10. When the Nvidia GTX is selected within Civ6 the game starts off fine. The GPU is ~30-40% usage and CPU is ~10-20%. After 5 to 15 minutes the FPS drops way off and audio is horrible. GPU usage goes to 0% and CPU goes...