Power Consumption
For all of the performance tests, we disable all power-saving technology in order to give us a consistent set of results, and to give us best-case performance numbers - even though technologies such as Intel's SpeedStep might only take microseconds to kick in, that can make a difference in some tests.
However, for the power consumption tests we re-enable everything in order to get a real-world power draw. The power draw is measured via a power meter at the wall, so the numbers below represent the
total system power draw from the mains, not the power consumption of a CPU itself. Measuring the power draw of any individual component in a PC is tricky to impossible to achieve.
Idle Power Consumption
For this test, we leave the PC doing nothing but displaying the Windows 7 desktop (with Aero enabled) for a few minutes and record the wattage drawn from the wall via a power meter.
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Intel Core i3-2100 (3.1GHz)
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AMD A8-3850 (2.9GHz)
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AMD A8-3870K (3GHz)
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AMD A8-3870K (3.6GHz)
Watts, lower is better
Load Power Consumption
To generate a realistic load power consumption figure we need to load both the CPU and GPU portions of the processors. To do this we used the multitasking portion of our Media Benchmarks which performs a massive file backup (with encryption) using 7-Zip, while simultaneously playing back an HD movie file using mplayer, making it a demanding test for any PC. We observed the power draw readings during this test and took the peak level seen.
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Intel Core i3-2100 (3.1GHz)
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AMD A8-3850 (2.9GHz)
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AMD A8-3870K (3GHz)
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AMD A8-3870K (3.6GHz)
Watts, lower is better
Note: the AMD processor was tested in an ATX motherboard, while the Intel chip was tested in a micro-ATX board. This difference can account for up to 20W, as we found in our Energy Efficient Hardware feature.
Read our Performance Analysis
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