I would say that one of the major performance boosts of Zen over Bulldozer is the introduction of real SMT due to the expiration of the patents. Bulldozer had C

I would say that one of the major performance boosts of Zen over Bulldozer is the introduction of real SMT due to the expiration of the patents. Bulldozer had CMT which is not the same technique. CMT vs SMT (very simplified view): https://i.imgur.com/AcZnipK.png https://i.imgur.com/AcZnipK.png As you can see, with CMT, you have the same amount of ALUs than with SMT but a single thread can only use its dedicated ALU leaving the other one useless meanwhile SMT allows a single thread to use all ALUs.