I read somewhere that some motherboards provide a BIOS update that allows a AM2 to run a new AM2+ Phenom processor. I know the socket is the same, so that lead me to believe this is true. I'm thinking about upgrading the CPU anyway, so it appears the 8650 Phenom (x3) should clock slightly faster than the 6400+ (x2) and is a couple dollars less. Here's links to the board:
http://www.newegg.com/Product/Product.aspx?Item=N82E16813130057
http://products.amd.com/en-us/MotherboardDetail.aspx?id=28
http://global.msi.com.tw/index.php?func=downloaddetail&type=bios&maincat_no=1&prod_no=259 (MSI Website)
http://www.newegg.com/Product/Product.aspx?Item=N82E16813130057
http://products.amd.com/en-us/MotherboardDetail.aspx?id=28
http://global.msi.com.tw/index.php?func=downloaddetail&type=bios&maincat_no=1&prod_no=259 (MSI Website)