Testbed Configuration and Methodology
In order to make the results of our today’s test session interesting and useful for as many users as possible, we decided to study the effects of overclocking on power consumption using several popular processor models featuring different internal design and microarchitecture. Therefore, we put together four popular platforms: an LGA775, LGA1156, LGA1366 and Socket AM3. That is why the list of computer components involved in our today’s test session turned out pretty substantial:
- ASUS P5Q3 (LGA775, Intel P45, DDR3 SDRAM);
- ASUS P7P55D Premium (LGA1156, Intel P55 Express);
- Gigabyte EX58-UD5 (LGA1366, Intel X58 Express);
- Gigabyte MA785GT-UD3H (Socket AM3, AMD 785GX + SB750, DDR3 SDRAM).
- Memory: 2 x 2 GB, DDR3-1333 SDRAM, 9-9-9-27 (Kingston KHX1600C8D3K2/4GX);
- Graphics card: ATI Radeon HD 5870.
- HDD: Western Digital VelociRaptor WD3000HLFS.
- PSU: Tagan TG880-U33II (880 W).
- CPU cooler: Thermalright Ultra-120 eXtreme.
- Operating system: Microsoft Windows 7 Ultimate x64.
- Intel Chipset Driver 220.127.116.110;
- ATI Catalyst 10.1 Display Driver.
We used our in-house testing equipment that was described in detail in the article called “PC Power Consumption: How Many Watts Do We Need?”. Without going too much into details about the design of this unit we would like to say that the advantage of this device over electrical meters, amperemeters, current clamp meters, shunts and voltmeters is that it not only provides more precise readings, but also allows to interactively monitor the current changes along different power lines. As a result, we will offer you not only the average results, but also the maximum power consumption readings. We will also check not only the current sent to the mainboard through a special 12 V processor power connector, but also the currents the mainboard receives via standard 24-pin ATX power connector along 12, 5 and 3 V power lines. We must take all this data into account because many contemporary processors, mostly the ones made by Intel, use combination power circuitry that involves not only the individual 12 V processor power line.
I would also like to mention that when we talk about total system power consumption today, we will actually imply the reading taken not in front of but past the power supply unit. In other words, we do not take into account the PSU efficiency, but deal with “pure” power consumption readings taken off the individual system components separately and together as a whole.
Before we get to analyze the power consumption readings taken under different operational loads, let’s take a closer look at the CPUs that will participate in our today’s test session. In this part of our article we will try to overclock each processor and will see how its maximum power consumption changes.