corecpumulti-core
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
Hyper-threading exposes multiple logical cores for a single physical CPU core. In simple terms, hyper-threading makes context-switching more efficient for each CPU core.
Dual-core chips, on the other hand, actually have two physical CPU cores which can execute different processes simultaneously.
There are also other multi-core chips that have many more than two cores, and--as Svish mentioned--Intel's latest multi-core offerings also support Hyper-threading on all the cores.
You can use a CPU identification utility like CPU-Z to determine how many cores you have. As you can see near the bottom of the screenshot, the CPU in this case has 2 physical cores. If the number of threads is higher than the number of cores, Hyper-threading is enabled. To-date all consumer-oriented CPUs with Hyper-threading have 2 threads per core, so if HT is enabled, the number of threads will be 2x the number of cores.
If you have an Intel CPU, you can download Intel's CPU ID utility instead.
The problem was been that I had 2 different CPUs, one is X5450 and another is E5450. When I changed one of them, to be the same, problem is fixed.
Best Answer
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.