Virtually meaningless. I did notice a big difference changing out a steel 5lb rigid fork to a 1.5lb CF rigid fork, much easier to loft the front wheel on my fatbike...but for all suspension forks, it means nothing, the quality of damping and construction is far more important. The higher end forks with more serviceable systems that actually work in varied terrain mean a lot more than saving a little bit of weight. Usually the poor damping is what limits you as you try to go faster, the ride gets rougher and you get out of control.