That's a pretty common mistake my friend, the Ace CPU is a turbo version of the 600MHz one itself, but its not overclocked
And there's not even any major difference between 600 and 800MHz.
So i'm expecting that there will at least be a stable 1300MHz clock anyways (considering that Galaxy 3's 600MHz CPU could handle one
)
And as for the downloading bigger games thing, i am assuming you mean play a bigger as in a game which takes more RAM, then yes, it will of course be helpful