Processor advertised with 2 cores but PC shows 4 cores

Question

I recently purchased an Intel i5-650 processor. On the Intel site, this the technical specifications show that the processor should only have two cores.

http://www.intel.com/products/processor/corei5/specifications.htm

However, when I check the Performance tab in 'Windows Task Manager', it shows 4 sections under 'CPU Usage history', indicating 4 cores. Can someone confirm if I have two or four cores.

I have seen this behavior with two of my friends Intel i3 processors as well.

Thanks

Answer 1

What you are seeing is hyper-threading. This enables a single core to process 2 concurrent threads of execution. http://en.wikipedia.org/wiki/Hyper-threading Its not actually as good as having 4 cores, but it provides a speedup.