You'll want to list your GPU and Monitor at least. And you will want to specify what you consider a good/bad FPS.
Still, the basics would be that G-Sync on will control frame tearing within the VRR threshold. This varies by monitor. If you are below it, say 40FPS, then Adaptive V-Sync turns on which doubles up on frames. With V-Sync also on, the frame limit should be capped at the monitor's maximum refresh rate.
If V-Sync is off, it will stop using Sync past the monitor's refresh and push whatever is in the buffer to the screen when it refreshes (tearing will return)
Some games need to be in full screen or full screen windowed mode to work properly. You also need to make sure you have these enabled for G-Sync in the Nvidia control panel to use them.
CPU: Intel(R) Core(TM) i5-7400 CPU @ 3.00GHz
MOTHERBOARD: MSI Z270 GAMING M3 (MS-7A62)
RAM 1: G.SKill F4-3000C16-8GISB 8gb 3000mhz
RAM2: G.SKill F4-3000C16-8GISB 8gb 3000mhz
GPU: GIGABYTE GTX 1050 Ti OC 4GB (GV-N105TOC-4GD)
DRIVES: TOSHIBA DT01ACA050 | Serial number: 653DU9VGS & TOSHIBA DT01ACA100 | Serial number: 46I0XTRNS
POWER SUPPLY:
Seasonic Core GC 550W
HOUSE: NZXT
The problem is that in fps games (csgo, cs1.6)
if g-sync is not turned on, there is no hitbox in games, if g-sync is turned on, the game is not so smooth, but the hitbox is still bad, and if g-sync is turned on and v-sync is turned off fps limited to 162, the game is faster, but it is as if there is still a delay between the monitor and the GPU.