Most computers and monitors are natively set to 60Hz which is fine, but gaming can be so much better with more Hz.

With higher refresh rate on your screen means your game can run at the true FPS it was capable of. Running a game 200FPS to a 60Hz monitor is a great shame, and would likely lead to 'tearing' where your graphics miss-sync with the Hz of the display.

Enter the world of Hz and FPS...

If you have a powerful enough computer you can match your gameplay FPS to your monitor Hz, if you have a decent monitor as well. 

Here is a bit of a checklist you need to go 144hz:

1. Use a display port cable to be safe that you definitely can achieve 144hz. Some later versions of HDMI do more than 60hz but best to use DP and its 100%.
2. Use NVIDIA/AMD control panel to set (or check) your monitor is set to 144Hz (under “change resolution”)
3. Then finally make sure your game has the refresh rate selected to 144hz.
   1. Set any frame rate limit to 145FPS (1 above)
   2. Disable v-sync
   3. Ensure the Hz is set to 144hz (some games default to 60Hz still)

All those should enable you to get up and running with buttery frames.