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Overclocking

Unlike Intel, AMD decided not to involve more advanced manufacturing process for the production of their new processors. But despite this fact, we expect to see a certain improvement of their frequency potential anyway, because the enhancements of the 45 nm process introduced by AMD’s production partner, Globalfoundries Company, did in fact allow lowering the heat dissipation of each core even without the use of “fine” transistors.

To check out this hypothesis we tried overclocking Phenom II X6 1090T Black Edition processor. I would like to remind you that this processor boasts an unlocked clock frequency multiplier, which allows increasing its clock frequency fairly easily. Of course, we couldn’t pass on this great opportunity during our overclocking experiments. We used LinX 0.6.3 utility to test stability during overclocking. The CPU was cooled with Thermalright Ultra-120 eXtreme air-cooler. Turbo CORE technology was disabled during our overclocking tests.

First of all we decided to check how far we could push the frequency of our six-core Phenom II X6 1090T at its default Vcore. As we have revealed in one of our recent articles, this type of overclocking is the most energy-efficient one and doesn’t lead to dramatic increase in power consumption and heat dissipation.

Practical tests showed that the system remained stable at 3.7 GHz maximum frequency and nominal processor core voltage.

The funny thing is that without adjusting the CPU Vcore our processor reached a higher frequency than it would in Turbo mode, when its Vcore would be increased automatically. In other words, it looks like Turbo CORE doesn’t really need higher voltage to work just fine, but there is no way to disable the Vcore increase.

We also tried overclocking our processor by raising its Vcore. For this second part of our experiments we set the CPU core voltage to 1.475 V, which was exactly what the CPU Vcore would be in Turbo mode. We didn’t raise the voltage any further on purpose, because for a six-core processor it may increase power consumption and heat dissipation catastrophically. In this case we managed to pass stability tests at 4.0 GHz.

Here I would like to point out that our test CPU could load the OS and pass some tests even at 4.2 GHz frequency, but it failed a full stability check in this case. That is why we consider 4.0 GHz to be the final result of our overclocking tests. In other words, Thuban frequency potential is at least as good as that of quad-core Phenom II X4 processors. So, I am sure that overclocking fans will be very pleased with the new AMD offering.

Unfortunately, we can’t tell you anything about the temperatures of an overclocked Phenom II X6 1090T. The temperature readings reported by the CPU itself are incorrect and the numbers according to all diagnostic utilities are obviously lower than the actual values. Maybe the thermal diode in the first batch of six-core processors wasn’t calibrated right, or maybe this issue should be fixed in the mainboard BIOS. However, we can estimate the thermal and electrical parameters of the overclocked processor knowing that its actual power consumption at 4.0 GHz frequency under peak load is about 260 W.

4.0 GHz seems to be a pretty good achievement for Phenom II X6 1090T; this frequency is 25% higher than the nominal one. However, the performance of the overclocked six-core AMD processor turns out lower than anticipated. The results of our express-test indicate that clearly. During this test we compared the performance of our overclocked Phenom II X6 1090T against that of Core i7-930 also overclocked to 4.0 GHz.

Strange as it might seem, but a quad-core CPU on Intel Nehalem microarchitecture with Hyper-Threading technology overclocked to 4.0 GHz almost always outperforms six-core CPU from AMD. At the same time I can’t say that Thuban’s frequency potential is higher that of Core i7 CPUs on Lynnfield and Bloomfield cores. Therefore, there is only one possible conclusion here: microarchitecture of contemporary Intel processors makes them faster than AMD processors working at the same clock frequency. And even a 1.5 times increase in the number of computational cores can’t make up for that. That is why we again arrive to the same conclusion that AMD’s only weapon in the battle for consumers is their pricing policy.

However, Phenom II X6 1055T may become a pretty attractive solution for overclocking. This CPU competes against Core i5-750 that doesn’t support Hyper-Threading. And if the junior six-core AMD processor can overclock to 4.0 GHz, then it may end up being faster than its overclocked competitor.

 
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