The 5160 is an LGA771 CPU. the E6600 is an LGA775. The Xeon swap doesn't work on all motherboards. If you have an LGA775 MB that supports 1333fsb then it probably supports 45nm CPUs and you should have better option there anyway. E8600, E7500 with tape mod to 3.66Ghz. Unlocked X6800 would be another 2 core 65nm option. If you said what MB you have we could give you more specific advice.