The amount of electricity a computer needs is dependent not only on its components, but also the user’s habits. For example, leaving the PC on for 9 hours a day will mean less power use than running it at full capacity 24 hours a day. In the worst case, if AMD’s Cool’n’Quiet energy saving mode does not work, you could end up wasting an amount of electricity sufficient to light up a room.

Old news for Tom’s Hardware readers: the Phenom struggles with high energy loss levels while in standby mode. The power consumption of the chip can reach a value three times higher than that of the Athlon 64 X2, though when under constant load, it can take advantage of its strengths.

We analyzed and measured the energy consumption and electricity costs of 35 different AMD processors. Almost all of the released AM2 line processors were included, like the Phenom and the classic Athlon X2; also here are the “Efficient Energy” processors like the Athlon X2 BE and EE versions. On top of that, the new AMD 4000e series was also tested, and even the Sempron 64 and the old FX-62 were measured.

This test focuses wholly on power consumption. We are not measuring processors alone, but rather complete systems, because motherboard and components have a significant influence on power intake.

An AMD platform machine with a 790FX chipset does not waste much energy. We found that an average AMD PC system will only use about $111 (72 Euros) worth of electricity per year.