PS4 spec explanation

Could someone please explain to me how the gfx & ram was finalized on the console.

From my understanding thus far, the ps4 was opting for 4GB of ram. However, due to the good grace of some devs, they advised to use more. And since the price of that particular ram had fallen, they threw in 8GB's of it.

I suppose what I'm trying to say then is, when they went from 4GB upto 8GB of ram, had they already finalized on the gfx. I mean was the gfx made with 4GB in mind. And so could the gfx have potentially been quite a bit more powerful then had they known there would 8GB instead of 4GB?

I don't think so, they have know about the specs for a long time. It having G-DDR 5. It has around 6GB for games and rest for the OS