The main difference is that they have been able to shrink the die quite alot by moving down to a 90nm process, which lowers thermal dissapation, and in some cases can lower the power required to run the card.
Power considerations, and heat issues not withstanding; there is no real functionality changes in the transition. It just menas that the die is smaller.
The bigest advantage is that the smaller die means a higher yeild from each silicon wafer, which means cheaper manufacturing cost, resulting in higher profits, and aggressive pricing
He is saying that since they are smaller they can produce more of them with less cost. Which means lower prices for us, which in turn means more sales. Thats why Intel switched to 90nm back in the day and now they are jumping to 65 nm.