CPU Cores understanding.

[Jahvy]

I've always wondered how multiple-cores work on a CPU. Can anyone give me a rather simple and efficient explanation for this?

[KBGaming]

Think of it as a road.

 

I'll give you an example:

Lets say you have a 1 lane road. The represents a 1 core CPU.

The 1 core CPU wil have "traffic" since it's only 1 core, but you're putting a lot of stress on it. This will spend more time doing a process.

Now lets say you have a 2 lane road. This road will have less traffic, because each core is able to organize the work, making less stress, and less time spent to finish.

[parashpa]

Excellent example KBGaming.!

[Jahvy]

Thanks, great analogy. So lets say you have a 4.0 GHz CPU and you have a quad core processor, will each core have 1 GHz or the "lanes" depend on the "traffic" being applied?

[tornados2111]

No, you can't count it like that. Each core is running at 4Ghz but having the 4 cores will let the processor get a lot more done at the same time since it has the 4 lanes

[Jahvy]

So more cores = Better CPU multitasking?

[KBGaming]

So more cores = Better CPU multitasking?

 

Exactly

[dlf]

In an instance of game systems -

 

One core could control the weather

One core could control enemy AI

One core could could something else

[Glenwing]

Each process that a CPU handles is called a "thread".  Multiple cores allows the CPU to address multiple threads at once.  So the benefits of a multi-core CPU depend on how heavily threaded your workload is.  This will be a very basic example and not necessarily true in real life due to complications but will hopefully get the idea across;

 

If you have a dual-core CPU at 1GHz and a single-core CPU also at 1GHz, and you have them both calculate Pi to 1 million digits of accuracy, that calculation is just a single thread so both CPUs will finish at the same time because they are both running at 1GHz.

 

However, if you have them both calculate Pi to 1 million digits twice, the dual-core will finish twice as fast as the single-core CPU, because it will be able to do both calculations side by side, at the same time, while the single-core CPU will have to do them one at a time.

 

So depending on what kind of applications you are running, they may benefit from a few, strong cores, or may benefit from lots of cores even if the CPU is clocked at a lower frequency.  Games for example usually have just a few very heavy threads running, so going beyond a quad-core is not useful, and increasing the CPU frequency will give more benefit.  Meanwhile content creation applications like Adobe Photoshop or Premiere Pro tend to be very multi-threaded applications and optimized to take advantage of as many cores as you can give them.  Because, the type of calculations that are done for those programs are very "parallel" work, which means it consists of a very large amount of small calculations.  And in fact those Adobe applications benefit greatly from offloading work to the GPU, which is an integrated circuit much like a CPU, but with hundreds of very very weak cores rather than a few strong ones.