If my board has the AM2+ socket, the Gigabyte CPU processor support site (http://www.gigabyte.com/support-downloads/cpu-support-popup.aspx?pid=3003) doesn't even list my AMD 945 X4 cpu. The 945 (which CPU-Z says I have) is only listed on the AM3 socket list.
I need to open the computer to verify exactly what I have, I know the mb has the model no. printed on the edge of the board, how do I know which socket I have?
Update: The following from wikipedia:
As AM3 processors also support DDR2, they are backwards-compatible with Socket AM2/AM2+, contingent upon a BIOS update for the motherboard. Manufacturers including Asus,[5] Gigabyte,[6] and others have labeled existing AM2/AM2+ boards as being "AM3 Ready" or similar, indicating that BIOS support is provided for the specified boards. This allows existing AM2/AM2+ systems to upgrade the CPU without having to upgrade any other components.
This answers my question - apparently I can put an AMD 1100T X6 cpu in my AM2+ socket and it will work, even with my DDR2 memory. I'm learning all the time.