Kinda both right, if you can double the refresh rate of you're monitor then you'll see improvment, otherwise you can cause tearing and you should v-sync, unless you drop below you're montiors refresh rate in fps as this will cause you're framerate to be cut in half.
This argument don't really have much to do with the Op anyway,
Back on point, from what you posted i don't think theres much more you can do, i have issues like these too and i think its just more to do with the engine and netcode more then anything, just try make sure you have a constant fps.