In the old days, when things were simpler, CPUs had just one core. Meaning there was single set of ALU, registers, cache memory etc. However, as we progressed, things changed and the CPU started featuring multiple physical entities called cores under a single chipset. When we talk about what does processor count mean, we are generally referring to the idea of a core.
So basically, Processor Count refers to the amount of Cores a CPU has. A core is essentially a small processor built into a large CPU that is capable of independent computations. The number of cores varies greatly, with some sporting two cores and some beefed-up ones having up to 64 cores.
Each core handling one task will be independent of another core working on a different task. More cores let the CPU work on multiple tasks seamlessly.
In this articles, we look further at what processor count means and what a core actually entails.
There IS, however, a caveat. In the server category, some motherboards have multiple CPU slots which can take two or more separate CPUs for more demanding processing.
Here the “processor count” actually means the number of CPU chipsets itself and does not refer to the number of Cores.
What Does Processor Count Mean?
As mentioned earlier, processor count basically is the number of cores on a processor.
Additionally, a single CPU core can be broken down into virtual processing units known as threads or logical processors. More on this below.
How Processor Count Influences CPU Performance
It’s time to see what does processor count mean for overall computer performance.
Multitasking is a staple of modern-day computers. It’s what lets you work, have multiple browser tabs open, watch a video, and do several other things on your computer seamlessly.
Higher core counts let you run multiple applications concurrently since each core handles a different data stream on its thread(s). In this kind of application, the more threads running tasks, the better the performance.
Having many processors means better multitasking. Some processes like encoding, rendering, machine learning or those that rely on massive amounts of computation require you to have many different workers processing small chunks of data simultaneously.
While we have covered the basics till here, to learn about about what does processor count mean, what cores mean, what single core and multi core performance means, we recommend you reach the rest of the article.
What You Need to Know About Cores
Cores on a processor are by themselves individual processing units. This means that they come with actual capabilities to perform independent data processing. Think of it as a smaller processor within the main processor.
They share some resources like Level 3 cache, memory controllers, and the system interface which connect to other devices, however, the ALU, Control unit, and Level 1 and 2 cache are built internally into each core as far as the current architecture stands.
To understand the need of cores and how having more cores affect the performance let us start with understand what single core processors are/were.
Single Core Processors
In the early days of computing, processors only had one core. This was responsible for being the brain of the processor.
Some of the important sub units of CPU are as follows (You DON’T, need to know these for the purpose of this article)
- Arithmetic Logic Unit: Where the logical and arithmetic operating happen. If CPU is the brain of a computer. ALU is the brain of a CPU.
- Floating Point Unit: A supporting unit for ALU for performing computations with complex decimal number.
- Registers: Temporary storage for executing operations. Also server as status flags.
- Control Unit: For instruction execution. Works as the orchestrator.
- Cache: Very fast memory for fetching data and instruction.
All of these sub units within a Single Core are the key ingredients of the Fetch-Decode-Execute cycle.
Since a single core CPU has only a single set of the sub units it could only perform a single Fetch-Decode-Execute cycle at a time.
The scheduling algorithms used made it seem that the computer was multitasking, but in an actual sense, the core was just handling different processes and switching between them indiscernibly fast!
Limitations of Single Core and Introduction Of Multicore Processors
As the market demanded faster and faster performance from CPUs. Initially, the answer was to increase the clock speed of the single Core.
Hence, the single core clock speed of a Pentium III released in 1999, for instance, drastically improved over the single core clock speed of the Pentium II released in 1997.
This introduced two problems:
- Context Switch Overhead
As the clockspeed became higher and higher, so did the heat generation. Cooling requirement and the power consumption was just no feasible enough.
The other issue what the Context Switch Overheard. A Context Switch Overhead is basically a delay that happens when a CPU has to switch from one task to another. So if you switch from a Word Document to your Internet Browser, the CPU would experience a delay.
Now if you were to have two cores, you could have the Word document loaded onto one core and the Excel sheet onto the other, thus eliminating the Context Switch Overhead.
Therefore, in terms of multitasking efficiency, a single core processor was just enough great enough.
Hence, as the prospects of multitasking and parallel processing gained momentum and as market started demanding better performance, multiple cores came out to be the answer.
MultiCores vs Multi-CPU Approach
Early attempts of having more processing units in a computer had engineers redesign motherboards to make them accommodate multiple CPU sockets. More cores inherently meant higher operational efficiency of computers.
This had issues though, first was the increased hardware requirements. Each extra CPU needed cooling, motherboards required new tracks to connect all sockets to various I/O devices and controllers.
Ironically, the builds weren’t as efficient as early thought out because along came latency issues. But, with miniaturization, it became possible to fit multiple processors onto a single silicon chip, and this gave rise to multicore processors.
What is a Multi Core Processor?
A multicore processors is basically a CPU that has several independend smaller processors inside. This is also referred to as Processor Count.
Each core has its own ALU. FPU, registers, cache etc. There are few components that are shared across cores as well as such as the L3 cache memory, however, for the most part, each core works as an independent CPU.
The immediate benefit here is that it drastically improves the multitasking performance of a PC.
Single Core vs Multicore Performance
While having multiple cores, or processor count, can drastically improve the performance of a CPU, the Single Core performance is still a critical measurements of its prowess.
As the name suggests, single core performance refers to how well a singular core performs.
This is an important measure since there are many applications and tasks out there that heavily utilize a single core and do not scale well with multiple cores.
For instance, many games and tasks in professional software like designing in AutoCAD is heavily reliant on a single core performance over the multi core performance of a CPU.
This is not a rare, but a very common observation. Hence when you look at the benchmark results for a CPU from a test suite such as Cinebench, you will see that they typically talk about both Single and Multi Core performance separately.
The CPU frequency is the most commonly used measure of a computers single core performance. It is measured in Gigahertz (GHz) and higher values mean higher cycles which can be interpreted as a faster chip.
The individual performance of certain CPU cores depends on the design of the core, the architecture used. In many cases, however, single-cores tend to leverage higher clock speeds to boost performance when needed.
The Ryzen 5 5600X, for instance, has a base frequency of 3.7GHz. A single core can boost to 4.6GHz whereas all six cores combined max out at 4.2GHz.
Where Single-Core Performance Matters
Single-core performance is very useful on applications that aren’t well optimized or built to run on multicore systems.
Some games will benefit more from having single cores with higher clock speeds than having multiple cores, most of which will remain dormant.
However, having just one core on the entire chip will be a huge bottleneck. The CPU will spend a lot of time waiting for responses and access to resources.
This wastes precious instruction execution time, a problem that can be circumvented with multicore CPUs.
Multi Core Performance
Multi core performance is, again as the name suggests, the measure of how well the multiple cores working together perform.
Multiple cores have almost become a necessity since a typical computational needs have become so complex even for an average person.
After all, a typical PC can have so many background applications running at the same time. All those background operation would preferably require a thread of their own to run smoothly.
Therefore, even if your game or your software uses a single core at most, the overall performance of the PC will benefit from a higher core count.
Where Multicore Performance Matters
If you need to perform multiple operations simultaneously, you will benefit from a multicore processor. With several processors onboard, one core can handle one instruction while another waits for resources, and you will still get good performance benefits.
Works such as 3D modeling and rendering require a lot of parallel computing. This is also the same for things like virtualization, simulation, and video editing and encoding.
They make multitasking seamless and offer better performance. Gamers can enjoy the benefits as well since many newer titles can access multiple cores. At the same time, many simulation games that require fast and complex calculations also perform better on multicore processors.
These are however much more expensive. They are also harder to manage and build applications for them.
Threads, Multithreading and Logical Processor Count
As stated, cores are individual CPUs, each capable of performing its instruction cycle.
Multithreading (or hyperthreading for Intel CPUs and Hypertransport for AMD) breaks down the core into smaller processing-capable subunits called threads.
This lets, single cores can work on essentially two tasks at a time.
Every process your CPU performs gets assigned to a thread, and each core can have two threads. This means that a four-core multithreaded processor will have eight threads.
Your computer may read the threads as a processor as well. However, these are not physical processors but logical processors.
If you have a quad core processor with hyper threading. You may have an actual processor count of 4, but your system may show you a processor count of 8.
Each process that you initialize creates a thread and the thread gets executed. Multiple threads executing different processes concurrently makes it look like the CPU is multitasking.
Unlike cores, threads aren’t physical segments on the processor. They are entirely logical units of processing whereas cores are actual processors on the chip. The creation of such processes and their disposal is handled by the CPU scheduler.
Benefits of Multithreading
Multithreading improves CPU performance particularly for multitasking and rendering work. It can be very beneficial for single-core CPUs by allowing the one core to handle multiple tasks simultaneously.
Knowing what does processor count mean is essential if you’re planning on buying or building a PC. If you often do some demanding productive work that involves complex calculations and a lot of virtualization, you’ll benefit from having many cores.
For those building gaming PCs, having higher clock speeds is usually better since most games aren’t optimized to use more than just a few cores, and having some idle processors doesn’t offer much of a benefit besides running background tasks.
That said, having six cores for gaming is a sweet spot. You can have more for productivity and futureproofing.