Clarkdale Efficiency: The Perfect Clock Rate For Intel's Core i5-661

Benchmark Results: Power Efficiency

Let’s start with the runtime of our efficiency benchmark, which consists of the following applications: 3ds Max, DivX, Xvid, Lame, MainConcept, PDF Creation using Adobe Acrobat 9 and Microsoft PowerPoint 2007, Photoshop CS4, AVG Anti-Virus, WinRAR, and WinZip 12. We saw a runtime decrease from almost 30 minutes on stock clock speeds to less than 26 minutes at the highest overclock.

These are the average power requirements for the efficiency test run and each of the test clock speeds.

We also tracked the total power used during this benchmark. It's interesting to see that the first three settings require exactly the same total power, while performance keeps going up from one test to the next. Now we can look at the efficiency score that divides the performance result by the power used.

You could almost tell by the total power used what performance you’d get this is the ranking. Overclocking to 3.7 GHz with 3.85/4.0 GHz Turbo Boost clock speeds is the most reasonable overclock, delivering the best performance per watt.

While other processor architectures show increasing power efficiency with a bit of overclocking, the Core i5 dual-core does not. However, going after too much clock speed causes a decrease in efficiency (while still delivering more performance, of course).