dedi is the way to go, if you dig your PhysX. especially if you go (or would even consider going) sli. 750ti minimum imo. (witcher3 in mind) tbh i'd prolly say 760 min with that game in mind) especially 120 /144hz users./
Physx card is always worth it, in my personal experience with a 780ti when physx is massively used, there are slowdowns. Borderlands 2, Arkham Asylum/City, Metro LL, Assassin's creed 4 all drop fps with physx on. So, if you are hellbent on having physx on and don't like fps drops too much, a dedicated physx card is a must.
