at 3.5ghz with my ram at 1:1,it is running at 1000mhz.you will need "good" 800 ram that will do 500(stock is 400(400x2=800)),unless with that 680 board you run fsb at 500 and ram at 400.1:1 is better tho'.
at 3.5ghz with mem at 1000 1:1 my system murders games.with a 8800gts/x my system would