Overclocking: Can Sandy Bridge-E Be Made More Efficient?

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Intel's six-core processors are fast, but enthusiasts almost always want to push unlocked multipliers harder. Core i7-3960X can easily exceed 4 GHz, but what happens to power efficiency when clock rates go up? Sandy Bridge-E demonstrates weaknesses there.

Overall Efficiency: Single- And Multi-Threaded

The system needed about 30% more average system power to make this happen, though.

And here, the average energy requirement rose by about 18%

This doesn't always happen, but Intel's Core i7-3960X achieves its best efficiency right at its stock clock rate of 3.3 GHz, with Turbo Boost taking it up to 3.9 GHz in lightly-threaded workloads. Yes, there's plenty more performance to milk from Intel's flagship, but it comes at the cost of even great power use. In the end, a negative impact on efficiency draws the direction of our chart downward.

Then again, if you're spending $1050 on a processor (or even $600, if you want the Core i7-3930K), a few bucks here and there on the power bill probably isn't too big of a concern. Believe us, the point of these chips isn't lost on our enthusiast-oriented minds. But we do find it useful to know exactly what happens as a consequence of tweaking ratios and voltages in the name of more speed.

Patrick Schmid
Patrick Schmid
Editor-in-Chief (2005-2006)

Patrick Schmid was the editor-in-chief for Tom's Hardware from 2005 to 2006. He wrote numerous articles on a wide range of hardware topics, including storage, CPUs, and system builds.