I actually like playing on slow too, but I switched to normal because of the running in mud glitch. I haven't tested these on anything but normal but I would imagine they will play pretty much the same on slow. As far as speed threshold, it's really a personal preference. I haven't tested these sliders on anything lower than 80. I think it gets more and more unrealistic the lower u go with it. There really isn't that big of a difference between the "fast" and "slow" guys in the nfl.