When I installed Grip I was doing about 60 FPS during the game. I was in settings and turned off VSYNC and according to the NVIDIA Performance Overlay (Alt+R) I'm getting 250 FPS sitting on the menu screen. I've uninstalled and reinstalled the game three times and rebooted the last uninstall and I'm still seeing 250 FPS on the menu screen.

HELP!

V-sync is effectivily a framelimiter that synchronizes the framerate to the displays refresh rate in order to prevent screentearing issues.

So when you turn it off, your gpu will put out as many frames as it can which will offer a more responsive gameplay experience but sometimes at the cost of higher energy consumption, more heat and noise of the gpu and in the worst case... screentearing.

There are other forms of limiting framerate and often they're beneficial to use over v-sync, like a hard framelimiter (easy to do with RTSS but sometimes not smooth and tearing), use scanline sync (hard to do with RTSS but smoother and no tearing) or use Nvidia's g-sync (hardware solution that must be supported by the display) or AMD's freesync (open source software solution that must be supported by the display)