Let’s take a look at a mainstream socket AM3 motherboard from ASUS based on AMD790X chipset with SB750 southbridge (and thus supporting ACC feature, that allows you to unlock hidden features on selected Phenom CPUs), M4A79XTD EVO.
ACC (Advanced Clock Calibration) present on SB750 south bridge chip allows you to unlock hidden features from certain Phenom processors: depending on the CPU model you can unlock extra memory cache and even one extra CPU core, in the case of triple-core CPUs. You can read more about this feature here and here. As mentioned this feature is supported on this motherboard.
Keep in mind that socket AM3 motherboards are compatible only with socket AM3 CPUs. While socket AM3 CPUs can only be installed on socket AM2+ motherboards, you cannot install socket AM2+ CPUs on socket AM3 motherboards. In fact AMD says that this installation will burn the CPU and the warranty doesn’t cover this situation.
The first thing we noticed on M4A79XTD EVO is the presence of only solid capacitors and the different design from the heatsinks.