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My system processor is Intel Pentium(R) Dual-Core CPU E5300 @ 2.60GHz.

My processor speed is 2.6 GHz as mentioned in process name. The processor name tells this is dual core.

My doubt is:

Processor speed is 2.6 GHz and CPU cores 2.

What is the meaning of 2 cores. I think 2 cores means (2.6 GHz + 2.6 GHz = 5.2 GHz).

Is my logic is right or not ?

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No. It is 2 cores, so think if it like 2 seperate cpus –  Dave Jul 27 at 10:27
    
possible duplicate of What is meant by the terms CPU, Core, Die and Package? –  Ƭᴇcʜιᴇ007 Jul 27 at 14:31

2 Answers 2

up vote 3 down vote accepted

A core is basically a CPU, just physically a multicore cpu is in one package. Unless you are in the habit of touching them you can thing of a core as a cpu.

You may be told a lot of hog wash about cores, such as with multiple cores you can run multiple tasks. Well you can run multiple tasks on one core/cpu. Multiple cores mean that your operating system has to split up the work, this is not always possible. Therefore 2.6GHz + 2.6GHz < 5.2GHz, and 2.6GHz + 2.6GHz ≥ 2.6GHz. Yes multi core can sometimes be only as good as one core. It all depends on OS, and usage.

Readers note: The + sign above is not normal addition, it is core addition. That is why 2.6GHz + 2.6GHz = 2.6GHz is possible.


Edit: see Paul A. Clayton's comment, it points out that multicore can at times be better than single, but only when all cores can be utilised (multi-thread/multi-process).

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Real world performance is much more complex than clock frequency. A higher performance single-threaded core can be limited by memory latency (ignoring diminishing performance returns for power and chip area budgets). Hardware multithreading increases the amount of memory-level parallelism, allowing more memory latency to be hidden (it also helps with branch resolution and execution latency). Multicore provides similar memory latency hiding benefits without the L1 cache contention. These techniques can turn a memory latency bottleneck into a memory bandwidth bottleneck. –  Paul A. Clayton Jul 27 at 19:03
    
I am sorry if the above comment was a bit harsh. The original poster was asking a simple question and not looking for a treastise on the tradeoffs in processor design. Your use of "hog wash" triggered a reflex that reacts to the belittling of the complex tradeoffs in processor design. Yes, some marketing has replaced the megahertz myth with the core-count myth, but both are at best coarse measures of performance which as you noted "all depends" (workload, non-core CPU and non-CPU system components). –  Paul A. Clayton Jul 27 at 19:04
    
@PaulA.Clayton thanks for pointing out some benefits of multi-core, what you say is true (if the work load allows, more that one thread). Thanks for also pointing out the Hz myth. –  richard Jul 27 at 19:17

"core" is hard stuff, so: two CPU's that can be handed separate tasks.

You may also have e.g. hyperthreading which then makes one/each CPU appear as more than one LOGICALLY.

Example: http://ark.intel.com/products/75122/Intel-Core-i7-4770-Processor-8M-Cache-up-to-3_90-GHz - 4 cores, 8 threads. 8 tasks can be run, but note that it will not provide / be equal to "8x efficiency/power" - there are bottlenecks and limitations.

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A tip related to this: look up GNU parallel and see if it is available for your OS (GNU/Linux; likely) - it is a tool that allows playing with this, and in certain situations it may well provide quite a boost for a task at hand - it is command line only as far as I know. –  Hannu Jul 27 at 12:21

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