Best way to mine would really depend on which coin you would mine. if its sha56  then you would really need ASIC miners since GPU wont able to mine such thing.We do know that Bitcoin cant really be mined by using GPU since it would really need asic miners which currently and the latest one is antminer s9 which do have 14+ th/s.We can point out that it is specialized to mine bitcoin and other coins which do have the same technical feature but on most cases on altcoins it can be mined by using GPU cards.