TweakTown posted a review on the memory performance of AMD Phenom II

AM3 based processors from AMD are designed with two integrated memory controllers; a 128bit wide DDR2 memory controller and a 128bit wide DDR3 memory controller. This is made possible thanks to DDR2 and DDR3 having the same mount of pins as DDR2 modules, just differently spaced. AMD has designed AM3 processors to be able to slot into AM2+ boards to run with their DDR2 memory controllers. However, you can also place the CPU into an AM3 based board to take full advantage of the DDR3 memory controller.

Now, this is a time of transition. AMD wants to get the AM3 based Phenom II’s out there and current AM2+ boards have already been given support for it. But what about users who don’t want to spend a fortune? - Jetway has come to the party with its AM2/AM3 combo board supporting both DDR2 and DDR3 memory slots onboard. Today we will see just how much difference there is in performance between using DDR2 and DDR3 memory thanks to this very board.

AMD Phenom II DDR2 vs. DDR3 Performance