Hello, When you are doing an overclock, you will more than likely have to adjust Vcore depending on the CPU and the amount of overclock. When folks refer to the Vcore values, are they talking about the values in the bios, or what it shows in CPU-Z or OCCT?

"mwilk",That's hard to say as most who go down the OC road use the actual bios setting value and the CPU-Z value at one point or another. Just as there are differences from one identical microprocessor to another due to the manufacturing process, there can also be differences between what value one sets in the system bios and what the voltage actually is, where it matters most, on your motherboard. This is an apple to oranges analogy, but it conveys the idea adequately enough.Typically, overclockers note what value they set in the bios setting then check the actual value on the motherboard via CPU-Z in order to make certain they are actually getting what they are asking for in the bios. I think this becomes more critical the greater a person is trying to tweak every last bit of speed they can out of their hardware.Hope this helps you understand a bit better.If you are going for a more aggressive overclock make sure you tweak your GTL REF voltages before you get to obsessed with pushing your Vcore voltage up as far as you dare. There is much stability to be gained from taking the time to find your optimum GTL REF voltages. You can read an explanation of them at this link.I have managed with an EVGA 780i mobo and a $60 air cooled heatsink to get my Q9650 running at 3.6GHz while using lower than stock voltage settings and being rock solid stable for a 24 hour Prime blend test with lower temperatures than I could even think of ever getting with my chip running at it's stock speed of 3.0GHz and it's stock heat sink.Pretty nice I think to be running my hardware 33% faster, using lower than stock bios voltage settings, while getting lower than normal temps not only across all four cores, but every where else in my rig as well. I use an Antec 900 case and am strictly air-cooled. At full load testing with Prime my cores reach a maximum temperature of only 55 - 60 *C. Completely safe overclocking is possible with minimal cost and can actually benefit the life of your system (by having it run at lower temps) if you do it right.You are doing the right thing though, educating yourself is the first necessary step, imho, to achieving excellent oc results. Regards

Av, Thanks for the reply. I was shooting for a 4.0 GHZ on my Q9550. At 3.9 GHZ I can keep my Vcore fairly low. (1.23v) Stable for 1 hour with OCCT. When I try to move to 4.0 I really have to increase the Vcore. I've seen numbers all over the place for Vcore. Some as low as 1.23v for a 4.0 o/c. I'm not sure exactly how they do it. I 'm not sure also that my memory is fast enough to support that high of an o/c. I may be better off to back it down some. I wonder some times, how much of a performance difference there is between 3.6 and 4.0.