So what we are learning is that even at 1080p even 4GB is becoming less and less valuable and optimally you'd want 8GB of vram. Good to know. I was planning on getting a 480 4GB, but now I think going for 470 8GB might be more future proof, when its pretty much the same price at $210 here.
I mean so far obviously a 4GB 480 gives better performance, games do seem to manage memory rather well and are efficient even with less memory than optimally needed, but the trend is clear, right now 3GB is utter garbage and worthless at purchase, 4GB is going to become worthless in about 6 months from now, especially as more games are DX12 developed as they seem to like more memory.
So at least following the last 6-7 benchmarks from various triple-A games 8GB memory is where its at, if you want futureproof you want 8GB of ram.