i have the quad core in my computer. When I go to the task manager and look under the cpu, I see all four cores. And whenever I run a program (for example 1 program) it shows the activity in the third core. Here is a sample that I found of what it does..
The multiple cores of the Kentsfield most benefit applications that can easily be broken into a small number of parallel threads (such as audio and video transcoding, data compression, video editing, 3D rendering and ray-tracing). To take a specific example, multi-threaded games such as Crysis and Gears of War which must perform multiple simultaneous tasks such as AI, audio and physics benefit from the quad-core CPUs[32]. In such cases, the processing speed may increase relative to that of a single-CPU system by a factor approaching the number of CPUs. This should however be considered an upper limit as it presupposes the user-level software is well-threaded. To return to the above example, some tests have demonstrated that Crysis fails to take advantage of more than two cores at any given time [33]. On the other hand, the impact of this issue on broader system performance can be significantly reduced on systems which frequently handle numerous unrelated simultaneous tasks such as multi-user environments or desktops which execute background processes while the user is active. There is still however some overhead involved in coordinating execution of multiple processes or threads and scheduling them on multiple CPUs which scales with the number of threads/CPUs. Finally, on the hardware level there exists the possibility of bottlenecks arising from the sharing of memory and/or I/O bandwidth between processors.
