There is no way to know how far you can push your overclock. It depends on the exact tolerances of the silicon you received. The manufacturers certify that it will run at the stock speed and nothing more, and until you find out you simply cannot tell how much headroom there is. How far you (or anyone else) managed to push one chip has no effect on how far another chip can go. The motherboard you want depends a lot on how much you have to spend. AMD sells its chips unlocked which means that almost any motherboard will give you the ability to manipulate it. If you have a lot to spend then a top end motherboard (ie expensive) mobo will have better features but if you don't you'll be able to OC on almost any AM3 board.