big jumps in framerate makes the game laggy and its not important if you drop from 200fps to 120 or from 90 to 50. it still makes the game laggy. sure its always about engine how its written. first person shooter games has often FPS lock for maximum framerate. i dont think gta engine has this option. so v-sync is the only one solution. if you have a good display capable higher refresh rates (75 – 150Hz) youre the lucky man 😀
my gaming experience tells me 90 or 120 FPS is ideal for killing obsession