With computers now becoming household appliances sold in every mall, it becomes difficult to understand what differences exist between one model and another. Reading another article in this blog about all the things to know when buying a new computer, we mentioned the differences between processors and how their speed is measured.
The processor is the brain so the faster it is the faster the calculations will be.
The problem is the way manufacturers make the speed of multi-core processors quite confusing.
Until some time ago, when computers had only one processor, it was easy to understand how powerful it was because it was written "1 Ghz" to define its computing speed.
Today, however, with multi-core processors, it is more difficult to understand what you have in your hand and what the real speed of the set of processors is.
The technical question today is therefore: what it means to have a PC with a 4 core or quad core 3Ghz processor, and what is its effective speed "> Superuser.
The main reason why a 3GHz quad-core processor is never as fast as a single 12GHz core has to do with the various tasks performed in the CPU.
If it is a linear task that needs to be done step-by-step, it can only ever be running on a single core at any given time.
This limits the CPU power of a dual core system to half, or 1/4 in a quad core system.
However, if you need to perform a task made of instructions that can be processed independently of each other, then they can be executed simultaneously, from different cores.
So if you are running a single-threaded program, a 12GHz single-core processor is significantly faster while if the task can be divided into several parts, a 4-core processor could compete even if perhaps not achieving the performance of the single one. at 12GHz.
The main advantage of a multiple CPU system is responsiveness because the heavy task can be performed by a single core leaving the others free for other programs and jobs.
The theory that 4 cores from 3GHz = 1 from 12 GHz is nonsense in any situation, except in the theoretical case in which perfectly parallel and independent tasks are performed.
Modern applications are designed to take full advantage of all the cores of a CPU but always need a form of synchronization.
It is therefore a mistake to think that 4 x 3GHz = 12GHz, not because it is not theoretically exact but because it would be like saying that 4 apples make an orange.
GHz cannot simply be added up.
To conclude, a little practice:
Dual Core is the generic term for a CPU that has 2 cores.
Quad Core is a 4 core processor.
Intel i3 processors are dual core, i5 and i7 are instead (generally, quad core).
The difference is that the i7 use Hyper-Threading technology giving a total of 8 processing threads.
If you see a processor that has 4 cores rated at 3.5 GHz, it means that every single core has 3.5Ghz speed.
If you want to see the use of individual cores on your computer, you can go to the task manager, to the performance tab, and open the resource monitor.
You will notice that each core is used in parallel, with different percentages.
In another article, it is written how to disable "Core Parking" to take full advantage of the CPU on Windows 7.
Those who are more experienced on the subject can leave a comment to provide a more exhaustive and precise explanation.
In another article, how to measure computer power and hardware performance with benchmark programs
