only in previewThere's a couple of things to check. Does the screen tearing exist in the recording or only in the preview?
Have you tried disabling the second monitor or changing the refresh rates to 120 + 60 hz instead of 144 + 75? In the NVidia control panel. Is your Vsync option set? You should probably go in there and check to see if it's set to at least ON but FAST is pretty good, too.
thannks man its working :)When the tearing happens in the preview it means that the Vsync setting is either not switched on or your driver doesn't recognise an OBS profile.
You should go into your Nvidia profile and change the Vsync option which is set to "application-controlled" by default to either "On" or "fast". And if it still doesn't work. You can add a custom profile, select the obs64.exe process and add it there. Then restart the app. It should work without tearing.