HoloDust on 19 November 2012
Well, if it was 128bit wide bus (like in 360) it would double that 12.8GB/s to 25.6GB/s - if I'm not mistaken, it is like going from DDR3 to GDDR5 at the same clock (x2 vs x4 effective, so 2x difference). So, for the sake of comparison (though DDR3 part is 1600 effective, and GDDR5 is 4000, so 2.5x difference):
http://tech2.in.com/reviews/graphics-cards/his-hd-6670-1gb-ddr3-graphics-card/231692#show
