What does "X ghz" mean on multicore processors?

[ARVB Rocky]

So I have been looking lately on numerous processors and I stumbled upon the multicore processors. I came to see same ghz number in cpus having different numbers of cores e.g two processors giving 4.0 ghz but one having 6 cores while the other has 8. So which one in this case would be better to have? And is this 4.0 ghz achieved by every core in the cpu all together, or does each core produce 4.0 ghz speed?

 

[SchizTech]

The clock speed of the CPU applies to all cores. A quad core 3GHz is spec'd to run all four cores at 3GHz, for example. In general, having more cores can benefit software that is multi-core aware (not all software but the proportion should grow in time) and multi-tasking. The OS will generally feel more responsive on a multi-core system because it can allocate different tasks to different cores concurrently.

 

[jitpublisher]

IIf you buy a cpu that is advertised as having a 4ghz clock speed, and 4 cores, then you have 4 cores each capable of 4 ghz on their own.
There are many underlying factors that you must consider though. Multicore processors are capable of sharing the work load between the cores, indeed this can be a huge benefit if a program is written or coded to use multiple cores, which most modern programs will to some extent.
6 cores is no better than 4 cores if the program you are running can only use 1 or 2 cores, so you have to know what you are going to be doing with the computer. Each core can, and will run at different speeds independently from the other cores depending on work load. Just as the old single core processor would downclock automatically when no work was being preformed, so the do the multicore processors.
Multiple cores are great for people who multitask, the more programs you have running, those extra cores come in pretty handy.

 

[Shaun o]

Each core in a cpu runs at a set clock speed.
You do not add the speed of the cores together if its what you mean.

What ever is the speed rating of the cpu its for all the cores that are implemented in the cpu die.

The advantage of having more cores is processing power, because although speed is important, the more cores you have the more data you can process.

So it would take for example an eight core processor less time to process data than a four core or six core.

The speed of each core is never added together because they all run at the same speed giving the over all Ghz clock speed no matter how many cores it has.

 

[leeb2013]

But don't just go off cores and clocks. The efficiency of the cores is also important. Eg some 4 core cpus at 3.4ghz are better than some 8 core cpus at 4.4ghz and use significantly less power.