FCOM volume 4 has all the information on how the FMGC works with winds. There is an integration formula that applies a weighting factor of current winds as measured to entered winds based on distance. This is considered when looking at OPT altitudes, but remember the FMGC is a very, very primitive tool for OPT altitudes due to very limited data and simple algorithms when compared to a flight planning system. Sorry I don't have the exact reference at hand at present. There is also a good explanation of MCDU time predictions and their relationship to what you see on the PFD in the FCOM too. The simple answer is PFD uses current ground speed and the MCDU uses entered data, with corrected wind adjustments.