It all depends on the game but I know for sure you need higher resolution to get all the performance out of the HD7870.
If you where on 1080P I would suggest the I3 combo.
oh isee, im a bit confused, so you mean i need a rig that can maximize it's full potential so it can achieve good fps?
why will it be a bad choice having a 7870 overkilling a tiny resolution without even reaching it's full potential?
and i know the i3 is a bottleneck, but, crap,, i think i was brainteased lol..