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System Builder Marathon, Q4 2012: System Value Compared

Energy And Efficiency

I’m always amazed when charted values create an almost linear evolution from our most affordable to our most expensive builds, even when that progression happens in power consumption.

Priced nearly four times as high as the $500 build, my $2,000 PC draws a little less than four times its power.

The big question on our efficiency page is how much extra performance we get for a given increase in power. To figure that out, we first calculate the average performance difference. Our combined performance bar is weighted as 30% games, 60% other applications, and 10% hard drive performance.

Efficiency is easy to calculate when we rely on average power and average performance to compare energy and work, but the results from those calculations normally center around a baseline of 100%. Since nothing can be more than 100% efficient, we normalize the results by subtracting 100%. The chart shows how much more or less efficient each PC is, compared to our lowest-power configuration.

The $2,000 PC’s performance advantage overwhelms all of the extra power two Radeon HD 7970s in CrossFire consume, and it's able to top the baseline $500 build's efficiency by 14%.

Meanwhile, overclocking the $500 box's graphics card increases power use more than it helps performance. And Don's $1,000 setup is never able to outperform power draw compared to the Pentium-based reference point.