I am very impressed with the opteron 1XX series especially the dualcore models. If you have excellent cooling and mobo any of the 165+ series can reach 3Ghz. Typically you will see you best results in the 2.5Ghz to 2.7Ghz range @ 1.34 or 1.4 Vcore. Increase Vcore to 1.5+ and you will be able get 2.8Ghz+. I recommend keeping Vcore below 1.45V for longterm use but it will certainly run error free at 1.6V if you can keep the heat down. If you are thinking about getting a 170 over a 165, its max overclock potential is actually the same. The main difference is that it has a 10x multiplier vs a 9x mulitplier so you will not have to raise your FSB as high to reach the same speeds. If you do not have a overclocker friendly mobo then you will achieve better results overall with the opteron 170. Anything beyond that and it will be cheap to buy a better mobo than buy a better cpu. I can run 2.5Ghz at stock voltage or 2.86Ghz at 1.5v Its too bad they wont be making these anymore.