2GB is the way to go on ATI upper mid-range and high-end cards. Or if you want to go with Nvidia, there are also some GTX560 ti 2GB versions. Or if you can find a GTX480 for a bargain as stores are selling the last stock, that is also great. If you want to go with a GTX580, you should definitively go with the 3GB version. It's not that the card will use 3GB of VRAM right now, it could probably have 2GB, but Nvidia's memory bus makes it easier to be either 1.5 or 3, and since a GTX580 is not cheap to begin with, you won't regret paying a little more to get the right card.
The advice I give to everybody going for an upper midrange or high-end card now is to get 1.5GB, 2GB or 3GB.
1.28GB as seen on the GTX470 and 570 is not a wise investment in the future (some games already use that amount to it's full at 1680x1050), unless you game with lower quality settings or want to replace the card in six months. It's not a good long-term buy anymore. I bet Nvidia would have liked to sell the GTX570 with at least 1.5 GB, but cost reasons from their expensive to make GPU dictated that.
As to the min. fps question, I fully agree. Most sites already do, but it should be made always. Sometimes the min fps below a certain level (and certainly 22 fps vs 28fps makes a HUGE difference, it really does), just ruin the experience.
Bear in mind I'm talking to an OCN audience here. Some people will be just fine with a lower amount of VRAM and use lower quality settings. I've come across some people that start thinking in "good enough" terms. I've been there. But now I have a proper gaming card
This site is not the place for "good enough" LOL. Maybe you have to live with "good enough" and that's fine. But there is nothing wrong in wanting the best. It's what makes the industry go forward.Edited by tpi2007 - 5/5/11 at 7:30pm