FWD's by design lose less than RWD's of the same setup/parts. And both lose less than AWD systems of the same parts etc. The FWD system is much more efficient, it's common sense if you take a second to think about it. Much less friction and the power travels over less area. You may find some FWD cars with massive powertrain losses, but that is irrelevent. Most FWD cars are not trying to make absolute power, just reliability, durability, and cost effectiveness.