Dont be on win 7/8 ( DL algotrithem in compreessing has been update. ) for all further change and updates, Could also say win10+ only + according to steam better DL Ration for 1gb lines with compressed files system with effect any newer game devs change for game and patches.

And clear DL cache to get ride of local cached data, then validate game intergrity of files.

ps.
So technicaly you could DL old game steam files from game devs but not the new game patch.


ps
we are just steam user here, this is steam that did it not us.