I'm looking to upgrade an old AM2+ computer that I have laying around to use it for Folding@home. It currently has a single core sempron and I want to upgrade that. However, i can't find an AM2 or AM2+ cpu anywhere, but heard AM3 works on AM2+.
AMD has confirmed that AM3 processors work on AM2/AM2+ motherboards. Thus users of Socket AM2/AM2+ motherboards will be able to upgrade to AM3 processors, without replacing the motherboard or memory; should the motherboard manufacturer provide the appropriate BIOS update.
However, upgrading AM2/AM2+ processors to AM3 motherboards require the motherboard contains DDR2 SDRAM slots, because AM2/AM2+ processors lack the DDR3 memory controller. In addition, the CPU socket need to be a universal CPU socket design that can accept both AM2 and AM3 pin layouts, because two extra pins on the AM2/AM2+ processors and the change in contact placement (940 contacts for AM2/AM2+ processors, whereas 938 contacts for AM3 processors) makes the older processor mechanically incompatible with the reference new socket, preventing users from attempting to install an old chip on a non-compliant new board.