Power Consumption And Efficiency
The following chart reflects power consumption throughout our benchmark suite, which gets logged every two seconds. The long, straight section at the end represents 30 minutes of idle time inserted by our automated script to better reflect actual use when we calculate averages.
Our comparison is principally between Intel’s Pentium G3258 and AMD’s Athlon X4 750K. We’ve seen how both CPUs size up in the performance metrics, and now we get a better idea of how much power they pull down along the way.
All four configurations spike into similar territory. Three settle around the same idle power, while one (the stock Pentium G3258) idles quite a bit higher. Interestingly, this is the same behavior observed from Intel’s Core i7-4790K on MSI’s Z97 Gaming 7. Since the Core i7-4770K was fine, I’m inclined to believe there’s some firmware work to do for Intel’s newest multiplier-unlocked models.
That long stretch in the middle, which is our Visual Studio test, best represents a CPU-heavy task with no graphics intervention. It shows the stock Pentium using the least power, followed by the overclocked Pentium, the stock Athlon, and the overclocked Athlon, just as each CPU’s TDP would indicate.
Based on the length of the lines, we also see that the stock Pentium G3258 is the slowest entry, followed by the stock Athlon X4 750K. You can’t really see it behind the other lines, but the overclocked Pentium wraps up first.
When you average out power consumption across the entire line graph, you get the above chart. The stock Pentium G3258 should probably be quite a bit lower. However, because there appears to be an issue with it idling at stock clock rates, 30 minutes is spent more than 20 W too high.
At any rate, the overclocked Pentium certainly uses more power in its quest, due to the higher voltage and clock rate. But we also know it finishes the tasks we throw at it faster. Meanwhile, overclocking AMD’s Athlon X4 750K doesn’t have a profound impact on average power use at all. That likely indicates good things for efficiency.
A glance at the line graph gave us this same information, but we more clearly see the finishing order of our entire suite. Intel’s Pentium G3258 starts as the slowest contender and, through overclocking, ends up fastest.
Multiplying power consumption and run duration gives us a Wh rating for each system.
Intel’s Pentium G3258 starts off using little power. However, mediocre performance and a poor idle combine to delivery lackluster efficiency. Only the stock Athlon X4 750K is worse. Its performance is better than the Pentium’s, but a 100 W TDP hurts the equation.
Overclocking to 4.3 GHz helps the Athlon improve its performance even more without affecting power consumption much. But the Pentium can’t be stopped. Average power use jumps 10 W (12%), while the benchmark suite finishes 23% quicker. The result is a first-place finish in efficiency.