No I mean there's 6 or 7 fps difference between the two cards.
The issue I have with the 8gb is the price difference more than anything.
Generally $50-70 more depending on models.
That's the price of a 240gb ssd drive & If I were building a budget rig & going for the 4gb meant I could squeeze an ssd in I would 100% do that.
& really that's all there is to it , if you can afford the 8gb without compromising anything else go for it
The 4gb model though is still a very very good card.