Power Consumption

For these performance tests, we disable all power saving technology in order to give us a consistent set of results and 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 benchmarks.

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 are of 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.

Load Power Consumption

For this test, we want to only stress the CPU, so use the small fft stress test of Prime95 to fully load all available processors (logical as well as physical). We leave Aero enabled, and wait a few minutes for any power saving technology to kick in and for the power consumption to level out before taking our reading.


The combination of disabling SpeedStep and overvolting means there's a considerable difference in idle wattage, although your mileage with vary through different voltage use - even the i5-661 was notably better. Even though SpeedStep is useful, we disabled it because it left our system was more stable.

Under load and things are a lot better, where the i3-530 only adds 50W to the idle voltage compared to others that take considerably more power - the i5-750 for example. This is mostly because they have more physical transistors firing - where the Core i3-530 has two cores and four threads, the i5-750 has four full cores running.