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Here is all the data compiled into one diagram. We can see the wide margin of the starting frequency of 2933MHz already by just using air cooling and default voltage. The CPU scales very well from 1.275V to 1.35V, giving an increase in frequency of about 200-250MHz - irrespective of the cooling used. After that, the curves for the air and water cooling start to level out and for the last 50MHz, some substantial voltage increases were needed. Using the phase change cooling we noticed a weak trend of plateauing at 1.50V followed by a good scaling up to 1.60V. Just as with earlier Intel CPU's we notice a bigger need of lower temperatures than higher voltages when overclocking.
An overclock of about 800MHz of the fastest model in a processor series using air cooling is quite impressing. The Phase change systems allowed us to sharply increase the overclock and we finally reach an increase of 2GHz. This is mainly because of the optimizations Intel's done in its 65nm manufacturing process, along with a number of functions for improving energy saving. The substantially lower heat dissipation is clearly noticeable with our cooling systems. Even with voltages over 1.6V our coolers had no problem keeping the temperatures straight. At 4.6GHz the load was big enough to keep CPU temperatures over -100C with our cascade rig.
The purpose of this article was to give an overview of what one can expect from their Core 2 processor. The stepping of the one we tested is 5/B1 and is the direct predecessor to stepping 6/B2, which is the one that is available in retail boxes. When it comes to overclocking, there's not much of a difference from what we've seen around the net so far. One thing that we stated early was that our sample didn't belong to the crowd that overclocks very well. We've seen examples of several CPUs, even cheaper ones like the E6700 and the E6600, that exceeded our results by over 200 MHz in every level of cooling. As the processors are getting more and more common, we'll be able to make better general conclusions, but we still want to say that the results we've presented is on the small side of how well the Core 2 processors will perform.
For the complete review visit : Overclocking Intel Core 2 Extreme X6800