If you want to get into an understanding then its you who really need brush up on whats what.
As i said before 2Gb of vRam is fine at normal res, just a year ago 1GB of vRam was fine. And thats no longer the case is it?
Have a look at this user with the newly release Crysis 2. its using close to 3GB of vRam
http://forums.bit-tech.net/showthread.php?t=227936&highlight=2gb+vram
Just one screen @ 2560x1600, and 60+ FPS, but lucky for him he has a 3GB 7970.
Just because its ok today is no measure of it being ok tomorrow, its foolish to think it is, the amount of texture in games is increasing all the time, single screens are becoming bigger with higher resolutions. nothing stays as it is, if it did we would still be fine on 1GB cards for 1080P.