Phenom II X6 1055T Overclocking Experiments
Now that we have discussed all the theory it is time to apply our knowledge to real life situations. To check out the overclocking potential of our processor we put together the following testbed:
- ASUS M4A89GTD PRO/USB3 mainboard (Socket AM3, AMD 890GX + SB850, DDR3 SDRAM);
- 2 x 2 GB, DDR3-1600 SDRAM, 9-9-9-24 (Kingston KHX1600C8D3K2/4GX);
- ATI Radeon HD 5870 graphics card;
- Western Digital VelociRaptor (WD3000HLFS) HDD;
- Thermalright Ultra-120 eXtreme CPU cooler with Enermax Everest fan.
First of all we decided to check at what maximum speed our AMD Phenom II X6 1055T processor can work without any increase in its Vcore. This type of overclocking is especially interesting because it causes no serious growth of the processor power consumption and heat dissipation and therefore can easily be performed without any cooling system upgrade or high-capacity PSUs.
During the experiments on our six-core processor we managed to get it to run stably at the default voltage at 3.7 GHz frequency. The junior CPU from the six-core family also performed well and remained stable at the same frequency.
As you can see from the screenshot above, the base clock was increased to 265 MHz to achieve this result. We didn’t change any voltages and their automatic adjustment was disabled in the mainboard BIOS. Turbo Core technology was disabled, as we recommend, and the multipliers for HyperTransport bus and North Bridge built into the processor were lowered to 8x, which made the frequencies of corresponding system units just a little over 2.0 GHz.
The system remained completely stable in this case and successfully passed our stress-test by Linx 0.6.3 utility from Intel Linpack suite.
The second part of our overclocking experiments was performed at higher core voltage setting. On the one hand it allows reaching higher clock speeds, but on the other it causes serious increase in the processor power consumption and heat dissipation. Note that contemporary Socket AM3 mainboards do not disable power-saving technologies anymore when you manually increase the processor core voltage setting in the BIOS. It is sufficient to use the relative voltage adjustment option instead of absolute one in order for the overclocked processor to continue lowering its frequency and voltage for the sake of saving power in idle mode. In this case Cool’n’Quiet technology remains fully operational and your overclocked system doesn’t consume too much power in idle mode.
In the end we managed to get our Phenom II X6 1055T to work stably at 4.0 GHz. And this is when our processor repeated the results of the recently reviewed Phenom II X6 1090T with that only difference that during overclocking of the junior six-core CPU we increased the base clock instead of changing the clock multiplier.
We increased base clock frequency to 286 MHz in order to hit the 4 GHz barrier. The CPU core voltage in this case was set 0.175 V above the nominal at 1.475 V. Of course, we lowered the multiplier for the HuperTransport bus and the North Bridge inside the processor. We used 7x multipliers and the corresponding frequencies were approaching 2.0 GHz. I have to say that many computer enthusiasts overclock not only the CPU, but also the memory controller with the L3 cache without lowering the multiplier fo0r the integrated North Bridge that much, but we decided not to stress the CU any more than we have to, because this frequency doesn’t have any significant effect on the overall system performance.
As for the thermal mode of our overclocked processor, it seems to remain quite acceptable. But unfortunately, we can’t claim that with all certainty, because the thermal diode in the first batch of Phenom II X6 processors appeared to be improperly calibrated. As a result, processors were reporting obviously lower temperatures. For example, as you can see on the screenshot, the CPU reported its core temperature to be no higher than 55°C (gray graph), while the mainboard diode beneath the CPU socket (yellow graph) read the CPU temp as 65°C.