what make v-sync worse ?
And of course it is a fps problem, in meaning of “more fps, more load”. Simple limit to a fixed 30fps MAX ( like the console it do ) and you get less system load - and not let the GPU compute allways whats maximal possible. Of course the settings you choosen have also an impact.
And the topic, your own , is so far I understand not about download speeds ( where I have zero issues ):