When compared on different makes and model boards the fsb, HT, DDR2 800, and a few others things are very much the same. The 590 is a slight upgrade as far as the chipset itself. One way to make a good comparison is to look over two different Asus models, one with the 570, one with the 590. A good look over of the specifications will see that other then the slight difference seen with the chipset the other features and capabilities are ??? close
For the 570,
http://www.newegg.com/Product/Product.asp?Item=N82E16813131013
For one of three 590 models seen,
http://www.newegg.com/Product/Product.asp?Item=N82E16813131011
The model with the 570 sees a lower cost and run 6 sata drives while the more expensive 590 model will run 8 sata drives. Both support SLI and will run 8gb of DDR2 800 memory. The main difference is a slightly newer and faster chipset while other things like memory, video and sound(optional) cards, supply, hard drive(s), and the OS will play the bigger role.
