I think the 2GB thing, is because of people that still look at graphics cards only in terms of how much memory they carry... I'm sure they overcharge for it so they make some more money off the ignorance of some consumers.All 3 of these cards are the same card in that they all will play games equally bad.
I know this is not what the cards are made for, but Nvidia is hoping grandma will pay an extra $30 for a "prettier" display.
And while underhanded does make sense economically.
What does not make sense is why give 1 of those cards 2 gigabytes of ram when it has no reason to have 2 gigabytes of ram. Any game you try to play besides DOS games will run at super low fps without anti-aliasing. Nvidia could shave $20 bucks or so off the price or even just pocket it rather than give the card 2 gigabytes of ram.