i agree with the others. the 448 is the better choice. having 2gb of memory does not make it faster, it will however make is smoother depending on the application.
And the 448 core does have 1280Mb of ram, so it's not like its only 1Gb .Helltech is also coorrect about the matter of sli. These were a limited edition card, and will likely be hard to find by next year