We revisit the problem of estimating the nonlinear channel capacity of fiber-optic systems. By taking advantage of the fact that a large fraction of the nonlinear interference between different wavelength-division-multiplexed channels manifests itself as phase noise, and by accounting for the long temporal correlations of this noise, we show that the capacity is notably higher than what is currently assumed. This advantage translates into nearly doubling of the link distance for a fixed transmission rate.