Would an atlon II x2 260- 3.2 ghz, socket am3,,,,,,,,,,,,,be a lot faster than a amd atlon 64 x2 2400 , 2.2 ghz socket 939
It would be. If you are going to spend money on a new motherboard and an Athlon II, I'd recommend you at least try to get an X3. The extra cores will greatly improve your system performance and the price difference is marginal.
Yes. But not by that much. I'd recommend you spend enough for an Athlon X4, it's only $90.