System Power Consumption

The four result values are as following:

• AMD Cool'n'Quiet / Intel SpeedStep: Windows Vista with Aero off, sitting at the desktop (1920x1080 32-bit) all windows closed, drivers installed. Processors have their power saving technology enabled, left in idle until power draw is stable.
• Idle: Windows Vista with Aero off, sitting at the desktop (1920x1080 32-bit) all windows closed, drivers installed. Processors have their power saving technology disabled, left in idle until power draw is stable.
• Load: Prime95 is used to increase load on all available cores and measurements are taken when power draw is stable

As you can see from the charts below, Athlon II X4 620 is not the most power efficient quad core processor, Intel’s old Q8200 is still getting the better of it, but not by far. You can also see the difference between Propus and Deneb cores running at the same clock and same 1.4V core voltage. Nevertheless, these are quite acceptable results for the new Athlon II X4.



Most of the time we just think of increasing the voltages and clock speeds to get better performance out of the processor. But Athlon II X4 is not all about pure performance, it wants to be the best all-round processor, completing every possible task fast and with high power efficiency. So, what if you are satisfied with the speed that Athlon II X4 620 provides, but want to save more on power consumption?

Our review sample was able to work stable at stock frequency by using just 1.175V on core voltage. That’s 0.225V less than the stock voltage AMD has set, and this simple voltage reduction brings great improvements in power consumption. Surely AMD is aware of this potential, but possibly wants to use it just for energy efficient models, that will come with lower frequencies and even lower voltages and power consumption. But it’s good to know even regular models, from first batches can save some energy by simple tweaks.

Heat

When recording core temperatures in Idle, the processor is left idling at the desktop, until it has reached stable temperature values. Same goes for Load temperatures, that are taken using Prime95 with 100% load on all cores. All processors were cooled by a Scythe Mugen 2, using 120 mm fan at 1200 RPM.

Most of the first revision Phenom processors come with faulty temperature sensors that give unrealistic temperature readings. Phenom II X2 and X3 models in this test are unfortunately one of those with faulty sensor so no readings for them are available.

Athlon II X4 620 runs much cooler than Intel’s Q8200, Intel’s uneven heatspreader must be taken in account here. Removing L3 cache from the die also decreased the temperature by a few degrees.
The stock AMD heatsink that is provided with the processor is sufficient for normal operation, but it cannot cope well with additional heat output when overclocking and gets very noisy very quickly.