  Parton distributions with QED corrections open new scenarios for high
precision physics. We recall the need for accurate and improved predictions
which keeps into account higher order QCD corrections together with electroweak
effects. We study predictions obtained with the improved Born approximation and
the $G_{\mu}$ scheme by using two public codes: DYNNLO and HORACE. We focus our
attention on the Drell-Yan Z-boson invariant mass distribution at low- and
high-mass regions, recently measured by the ATLAS experiment and we estimate
the impact of each component of the final prediction. We show that electroweak
corrections are larger than PDF uncertainties for modern PDF sets and therefore
such corrections are necessary to improve the extraction of future PDF sets.
