Quote Originally Posted by mbox_bob View Post
1070's are 8GB usually. 6GB cards are the 1060's.

That said, I'd say a 1070 is about on par with a 980Ti (they trade a bit of tit for tat). Comparisons for 980 vs 1070 indicate somewhere around the 25% better mark (all fairly subjective results, but definitely a marked improvement).
So I'd say a step up.
I have a 980Ti in my unit and a 1070 in Mom's multiboxing unit and the 1070 seems to have a little more headroom than the 980Ti in DX11/DX12 apps. It also runs a little cooler and draws a little less power. I would put my real-world experience comparing WoW, synthetic benchmarks, and general performance at somewhere around a 5-10% difference at most between the two depending on how many of the current DX12 effects are implemented in the game. Considering they were about the same price when I bought them, it was mostly a wash and would take paying close attention to numbers to notice any real difference.

My 2 copper, anyway.