AMD will not likely be able to match Intel's scale of manufacturing & production anytime soon, so they're taking the other direction: make the chips "smarter." Expanding SSE will hopefully accomplish that goal.

"AMD designers examined existing instruction sets, such as the Apple/IBM/Freescale Altivec instruction set, then identified three software types to optimize SSE5 around: compute-intensive applications, such as financial simulation and life sciences; multimedia applications, like high-definition video encoding and image processing; and security applications, where data is encrypted across the Internet as well as an entire hard drive."