The processor typically is the most power hungry component inside an average desktop PC. CPU power consumption first became a real issue as Intel closed in on 4 GHz with its Pentium 4, where 100+ watts was required and optimized cooling became a necessity. However, power requirements and performance did not match up with this chip. The advent of the first Pentium D 800 dual core processor made things even worse, until Core 2 Duo came to the rescue 18 months ago. We have since seen a 400% performance per watt increase, from the Pentium 4 600 series to the recent Core 2 processors. We’ll look at some details of that evolution in this article.

When we looked at the typical power consumption of two AMD and Intel systems, we tracked the total power required to perform real-life tasks over time, simulated by BAPCo’s SYSmark 2007. This benchmark is based on real-life applications, which process real-life workflows in a multitasking environment. While most publications release test results of minimum and maximum power requirements of components and systems, these results only tell a small part of the story. Power consumption has to be related to performance at all times, because a faster system may return to a more energy-efficient state earlier than a slow machine, and thus consume less power over time, even though the faster solution might have a higher maximum power requirement.

Our first article dealt with an AMD Athlon 64 X2 5000+ (65 nm) and Intel’s Core 2 Duo E6400. Both are fast and efficient dual core processors, but Intel’s Core 2 Duo won the efficiency battle due to its performance advantage, allowing it to resume an idle state quicker than the AMD processor. But how does the Core 2 Duo compare to the Core 2 Quad? And how much better is it when compared to the Pentium 4 and the Pentium D? Let’s have a look!