Power Consumption And Efficiency
e-on’s Vue 8 turned out to be the best candidate for measuring system load power because it’s a nice, long workload, and it fully taxes each of these configurations.
We already knew the finishing order from our performance tests. Now we can add to that power use over time, thanks to our Extech logger.
As the line graph suggested, Intel’s Xeon E5-2687Ws average the highest power consumption in this workload (then again, we might have guessed that would be the case, given two CPUs with 150 W TDPs).
Surprisingly, the Xeon W5580s are the second-worst offenders. Remember that Intel switched to 32 nm manufacturing for its Xeon 5600 series, so even though those processors sport an additional two cores each, they’re able to outperform 5500s in threaded apps while using less power.
Naturally, a single Core i7-3960X offers the absolute lowest average power numbers, albeit with the worst performance.
Multiply the average power by the fraction of an hour each configuration took to finish its rendering task and you end up with energy use in Watt-hours.
High power use and mediocre performance really hurt the old Xeon 5500s here. In comparison, the 5600s are much more attractive (though they use marginally more energy than a single Core i7-3960X, which is slow but draws a lot less from the wall).
The real winners are Intel’s Xeon E5s, though. Despite averaging the highest power consumption, stellar performance under a full load translates to the lowest energy use.