Atomic Systems

I need some clarifying here to make sure I'm understanding this correctly. I know my original question was about UE4, but lets use TS2015 as an example. So if I have a dual core cpu (say an i3) and I'm running TS2015, its only using one of the two cores correct? What would the benefit of stepping up...

I know the UE4 version of TS won't be out for awhile, but have they mentioned if UE4 will utilize hyperthreading or not? I'll be curious to see if it does and how much of a performance increase it'll add compared to a non hyperthreaded CPUs. Anyone have any thoughts on this?