Go to Documents\Assassin's Creed Unity\ACU.ini (or Assassin's Creed Unity.ini ). Find: NumOfCores = 4 Change it to NumOfCores = 8 or however many threads your CPU has.
Many repacks offer "selective" downloads, allowing you to skip unnecessary files like extra language voice packs or co-op mission videos to further save space. System Requirements for PC download assassin-s creed unity pc highly compressed
But remember: If you love the game, buy it later. Support the developers so we can get a proper next-gen Assassin's Creed that doesn't need compression in the first place. Go to Documents\Assassin's Creed Unity\ACU
"Highly compressed" versions, often called repacks, use advanced compression to make the game easier to download for those with limited bandwidth. often called repacks