Wow, some people are being completely unreasonable with this future proof stuff, like 4gb is some magical number.
So when the card had 4gb it was ok, totally futured proofed, you are set for the years to come, no problem. Now at 3.5 it's omg this piece of shit won't even run games proporly 6 months from now.
Now, don't get me wrong, I totally get that people are upset for being lied to. You basically bought a 4gb card and got a 3.5gb one. I get that, it sucks. But I guess I just don't get the rush to get a refund. If you are doing out of principle I totally understand (unless you are going to buy a 980, in this case it makes no sense), but if you are doing it because suddenly your card supposedly isn't future proofed anymore... that's just silly. If your 970 will not be enough for you next year, chances are a hypothetical 4gb one wouldn't either. If you are bothered by not being able to max everything you wouldn't stick with a 970 either way.