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Overclocking Specifics

In our article called “Guide: Lynnfield Overclocking on Asus P7P55D Deluxe Mainboard” we described the major overclocking techniques and demonstrated a few typical examples of how the new processors should be overclocked. Of course, everything we said is also true for Gigabyte GA-P55-UD6 mainboard, although it does indeed have a few peculiarities of its own. Most importantly, Gigabyte mainboard doesn’t allow overclocking the processor by raising its Vcore with all Intel CPU power-saving technologies remaining up and running. Therefore, there are at least three following overclocking approaches that we should take into account:

  • Maximum possible overclocking with processor Vcore increase at the expense of giving up Intel processor power-saving technologies;
  • A little lower overclocking, limited by the nominal processor Vcore with static implementation of Turbo Boost technology, but with all power-saving technologies up and running;
  • Even lower overclocking with dynamic implementation of Turbo Boost technology, which ensures more flexible response to various load levels; again limited by the nominal processor Vcore but with all processor power-saving technologies up and running.

At first let’s find out the maximum base frequency at which Gigabyte GA-P55-UD6 mainboard remains stable. Just like for Asus P7P55D Deluxe, the maximum was 210 MHz, but we had to raise the IMC Voltage of the North Bridge part integrated into the processor much higher this time: from 1.1 V to 1.3 V. New mainboards based on Intel P55 Express chipset do not require increasing this voltage in order to ensure that the memory will work at high frequencies. However, the boards do require higher voltage setting when the base frequency is increased past 170-180 MHz.

We used static Turbo Boost implementation, i.e. we limited the processor clock frequency multiplier by 22x maximum for our Core i7-860 CPU. In this case we managed to get our system to work stably at 180 MHz base clock. We could formally provide you the screenshots from applications and even benchmark results proving that our system could work at 182 MHz base clock. In this case we get a beautiful resulting CPU frequency of 4.0 GHz. However, there are two reasons why we won’t do it. First, we had to raise the processor core voltage to 1.325 V, which pushed the CPU core temperature to 92 °C during our test session, which was way too high. However, we could have disregarded even this dangerous temperature increase. Anyway, LinX utility that is used as a shell for Intel Linpack application creates extreme processor load. We will hardly see the same high core temperature when we run some of the more common applications. However, this is where the second reason stepped in: at 182 MHz base clock we can set the memory frequency at 1820 MHz, but Gigabyte GA-P55-UD6 mainboard wouldn’t let us lower the timings to CAS Latency 7 level in this case. In fact, the memory can work with these timings at even higher frequencies, but in this case we had to increase CAS Latency to 8 in order to successfully pass all tests. I assumed it would be better to sacrifice 50 MHz of processor frequency, which wouldn’t have any noticeable effect on the resulting system performance, in order to ensure that the memory subsystem worked with relatively low timings.

This way we managed to overclock our Intel Core i7-860 processor on Gigabyte GA-P55-UD6 mainboard to maximum 3.96 GHz. This is a very impressive number. The processor Vcore only had to be increased to 1.2875 V, which immediately lowered the core temperatures to 85 °C.

You can easily see that this result is even higher than the one we obtained during the same CPU overclocking on Asus P7P55D Deluxe mainboard. Back then we had to work with 177 MHz base clock, which allowed to overclock our processor only to 3.9 GHz. However, do not forget that this time we used a more efficient Cooler Master GeminII CPU cooler instead of Scythe Zipang 2. In exact same testing conditions (with the Cooler Master CPU cooler), Asus mainboard demonstrated the same exact result, as the one obtained today on Gigabyte GA-P55-UD6.

The funny thing is that on two different mainboards, with slightly different voltage settings (Asus mainboard required 1.29375 V processor Vcore), the peak voltage under maximum processor load was still 1.312 V. However, the situation changes dramatically, when the CPU is idle. Asus P7P55D Deluxe has all Intel processor power-saving technologies up and running that is why in idle mode not only the processor clock frequency multiplier but also the core voltage get lower.

As for Gigabyte GA-P55-UD6, only the multiplier lowers, and the core voltage remains excessively high.

 
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