With the launch of Deneb, AMD has finally moved to the 45nm process and are breaking in a new socket interface at the same time. The main difference with AM3 is the introduction of DDR3 support. But rather than require a forklift upgrade, AMD has incorporated both DDR2 and DDR3 memory controllers into the AM3 chips. One of the first of these chips debuted last month with the tri core X3 BE 720, running at 2.8Ghz. But with only three cores, is the 720 even a viable upgrade for someone with a first generation Phenom quad or is it just a hamstrung slug of silicon?

http://www.ocia.net/reviews/amd720be/page1.shtml