I would wish to urge you to try with just two bars. Too prefer one in your kit double channel set and later that you can test with the other. It gives the solution with the coefficient multi / FSB / CPU / ratio fsb: ram / Ram frequency. Also I need to ask you that have you altered the subtimings your RAM? If yes, then how many? I imagine that if you furnish that, then I will capable to give you more appropriate result.