Far Cry 3 is greatly optimized. Stuff like AC4 and Watch dogs (Reletively recent titles) weren't well optimized I feel like there's been a shift in ideas or something recently. The really annoying thing, however, is that Ubisoft said throughout it's development that Watch dogs was going to be built from the ground up with PC in mind.. yet clearly we have a blatant console port.
Dunno.