Whats up with my video card????

Quick question, I might be getting a gaming computer later on in the year at ibuypower.com I realize that some graphics cards have a 2x before them, what does this mean? Does it double everything? So a 256 x2 would be 512... and it be double the graphics power?

/me confused

That means you are going to have TWO of those cards, which means more power, more performance, I don't know about two times the everything...

Ahh, so it would be better getting that than just getting a 512mb 7900gs or something.