I had the same problem with HUGE lags when aero is active on Dell 7510 (1575 xeon, 64gb RAM, 2gb of m2.ssd) that I bought over $5000 (jan 2017). I have two video cards on board - Nvidia Quadro M2000M and Intell. I guess Dell have problem with laptops that contain two video cards and vmware doesn't support it properly.
Solution that helped me is very simple and fast - just downgrade from 12.x to 10.x hardware compatibility (VM->Manage->Change Hardware Compatibility).