1. 60hz desktop refresh
2. 60 or 30 in obs
3. 60 in game if there is switch for it (like bf3, bf4, overwatch)
4. vsync in game on
5. run obs as admin
6. make sure your gpu can do stable 60fps in game without being maxed. OBS needs some of gpu resources as well. If you enabled vsync@60 and its still maxed lower resolution and/or details.
(replace with 59,94 and 29,97 for 59,94 display like hdmi tv)
with 144hz monitor its fastest and most reliable to sacrifice 144 and follow 1,2,3,4