X-bit labs

Phenom CPU: Christmas Gift from AMD (page 15)

Category: CPU

by Ilya Gavrichenkov

[ 12/19/2007 | 05:35 PM ]

Power Consumption Tests

To investigate the consumer potential of the new quad-core AMD processors to the full extent, we couldn’t avoid checking out their power consumption rates. I would like to stress that this is preliminary data because it was obtained on an engineering sample.

During our tests we compared the power consumption of the above described test platforms equipped with different processors: AMD Phenom and Intel Core 2 Quad. We measured the current going through the processor voltage regulator circuitry, thus estimating the power consumption of the CPUs themselves (not taking into account the losses inside the voltage regulator). The processors were loaded using Prime95 25.5 utility.

Enhanced Intel SpeedStep and Cool’n’Quiet 2.0 power-saving technologies were activated. Our Phenom CPU dropped its clock speed to 1.3GHz and its Vcore - to 1.05V in idle mode.

The diagram below shows results obtained in idle mode and maximum CPU utilization created with different number of threads (from one to four). This approach should show how efficient is Cool’n’Quiet 2.0 that can manage Phenom processor core frequencies independently.

Unfortunately, Phenom processors cannot boast low power consumption rates. Core 2 Quad Q6600 that is on average about 7% faster than Phenom 9900 consumes less power in idle mode as well as under workload. Although the Phenom power consumption curve shows that Cool’n’Quiet 2.0 actually works fine, it is not enough to beat the competitor from the energy-efficiency standpoint. Intel solution remains one of the best choices from the performance-per-watt prospective.