First of all, it should be noted that before 2006, with the launch of Intel’s Core 2, all CPUs were single-core and therefore single-processor. In other words, the historical trend has been to call the central chip of our computer a processor or CPU, but in reality we should call it the processor chip or CPUs. The reason? Each of the cores is a processor in itself, so if we say an AMD Ryzen or an Intel Core has 6 cores, we are saying that they actually have 6 processors, even though they are on the same chip.
The general confusion between core and processor
The idea is that they all work together, so in parts of programs that can be run in parallel, we’ll see multiple cores working together an efficient division of labor. Instead, there will be parts of the code where only one core is needed to show its potential. This is why, in each generation of processors, we seek not only to have the greatest possible number of cores, but also to improve the performance of each of them individually.
On the other hand, as they all have common access to the same RAM memory, they have a last level cache memory, common to all, which puts them in communication with a common memory controller. This allows them to be consistent with memory and know that any changes made to a program by one kernel are known to others and they can work in unison on the same programs and applications.
The other processors in the system
In your PC, there is not only the CPU, but also other types of cores and supporting processors. These are usually not counted because they are not inside the main motherboard chip, but are part of the whole computer. So if we are being strict, when asked how many processors my PC has, we should also count those found in the rest of the components.
How many processors can a PC have?
Well, it will depend on the type of computer we are talking about. We must start from three important points that differentiate server processors from those of conventional PCs.
- The more cores, the bigger the processor will be, and therefore the point will be reached where its cost will be prohibitive for the desktop market.
- More cores require more memory communication, since the RAM interface pins are always at the periphery, this will also mean a bigger chip.
- And obviously also a high number of cores will mean higher consumption.
So, to the question of how many processors a computer can have, the first answer is simple: as many as can fit on the chip. The other problem is the internal intercommunication between them. If you have few cores, four at most, you can use direct intercommunication, but beyond a certain number it complicates the circuitry, since it’s always the square of the number of cores.
That’s why in systems with 6 cores and more, ring pass-throughs are used, which are much simpler to set up, but with the disadvantage that adding more cores increases the latency between them and can be counterproductive for performance. In any case, there is a limit that can be placed and it will depend on the size assigned to the chip, the manufacturing node and the electrical power assigned. Decisions that are made early in the design phase.
Which processors are not
A processor is defined by the fact that it can perform all three main steps when processing an instruction. That is to say the capture (Fetch), the decoding (Decode) and the execution (Execute). We say this due to the fact that it’s common in graphics card marketing to call the ALUs that handle the last stage CUDA cores or stream processors. That is, it is like counting a part of an internal combustion engine as if it were an engine itself. Isn’t that absurd?
On the other hand, many applications when counting a processor’s execution threads count them as cores and when asked how many processors there are, they display them incorrectly. This is because they count threads of execution. And the catch is that modern kernels have duplicate parts of the capture and decode units to switch tasks on the fly if the main one gets stuck. That is to say, it is the same as when your PC continues to do a task with which you cannot interact and while you are waiting for it to finish, you take advantage of it to do other tasks. things.
Both elements do not answer the question of the number of processors because they are not complete units, whether it is a CPU or a GPU. By the way, in the latter we should count as processors or cores the number of computing units in AMD or SM in NVIDIA, which are in charge of the three main stages.
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