The Multi Core Myth
A multi-core CPU is not always a better performer than a single-core CPU. This fact depends upon many different factors, including the task at hand, the architecture of the CPU, etc. The following article provides a good bit of information on the factors surrounding this fact in detail. Check out the excerpt below or check out the full article here (scalibq.wordpress.com).
“…. The thing is, time and time again I see people recommending a CPU with more cores for applications that require more threads. As Johan de Gelas points out in the aforementioned article, it is not that simple. Although the Bulldozer-based Opterons have 16 cores, they often have trouble keeping up with the older 12 core Magny Cours-based Opterons.
Now, it seems there is a common misconception. Perhaps it is because the younger generations have grown up with multi-core processors only. At any rate, let me point out the following:
In order to use multiple cores at the same time, multiple threads are required. The inverse is not true!
That is: a single core is not limited to running a single thread. ….”