I am saying that each manufacturer competes with the other on a lot of different levels. They will put out a card that the real power users will go after , and then they will put out a card the above average person will go after amd so on down to the low budget person. Each card has a set of specifacations and feature set and you really have to do your home work by looking at all the review sites to see what cards are doing what performance with what games , and you have to find your card and the games you like and see what these sites say about them.The 192 and 256 bit you are refering to is the bus width and the bus width in comination with memory clock determine how many gigabits per second the card will produce. In the two cards you are refering to one has 2 gb ram while the ATI card has the wider bus and only 1 gb of ram. But that is not all that goes into what the make up of the card that would make one better than the other , Nvidia cards have cuda cores Ati does not , what is the core clock speed , what is the texture fill rate , what is the memory clock speed , that is why you have to do your homework and search out these other review sites.