Overclocking
Although triple-core Phenom X3 processors are based on the same B3 stepping as the quad-core AMD CPUs, we should pay special attention toe their overclocking potential. As there are fewer cores working simultaneously, the heat dissipation should also go down and theoretically it should allow achieving better overclocking results.
I would like to point out that Phenom X3 8750 processor we had at our disposal, just like other CPUs from the same family, features a locked clock frequency multiplier. That is why they should be overclocked by raising the clock generator frequency. This is not as easy to accomplish as we wish. The thing is that as we have already mentioned in our special article, this frequency is tied up not only to the resulting CPU frequency, but also to the frequency of the built-in North Bridge, memory and HyperTransport 3.0 bus. That is why when you increase the clock generator frequency, you should remember to reduce the corresponding coefficients and dividers forming the North Bridge, HyperTransport and DDR2 SDRAM frequencies.
For example, by raising the processor Vcore to 1.45V we could increase the clock generator frequency to 260MHz from the default 200MHz without losing stability. However, the North Bridge and HyperTrasnport frequency multipliers has to be set at 7x instead of the nominal 9x, thus keeping the corresponding frequencies close to their nominal values.
In this case Phenom X3 8750 processors overclocked to 3.1GHz frequency and remained absolutely stable. We tested stability with a one-hour run of prime 25.5 utility. To dissipate the heat from the overclocked processor we used Scythe Mugen (Infinity) air cooler.
I would like to say that 3.1GHz frequency is the best result for a K10 based processor that we managed to obtain in our lab so far. Therefore, we can hope that Phenom X3 processors are more overclocking-friendly than their quad-core fellows. However, we will be able to draw final conclusions only once we collect more data from the tests of more than one processor sample.
