Odd issue but when using desktop mode with a controller and I click the thumbstick to go into first person, the framerate drops to 0.1 per second.
I had to look up to the sky and repeatedly click to go back to third person as the whole system got bogged down so badly controller inputs weren't registering.
Specs aren't barren.
GPU: GeForce GTX 1060 6GB CPU: Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz Memory: 16 GB RAM (15.93 GB RAM usable)
I'd assume it's trying to do a VR headset thing when one isn't plugged in.