CPU (Central Processing Unit.) The name sounds a bit complicated, but that's exactly what a processor's role in a laptop is, and explains why it's also called the heart of a computer.
To put it simply, a processors takes instructions from RAM and executes them by performing some basic mathematical and logical operations. What exactly is to be done is dictated by a program that's been loaded into the computer's memory. The processor's clock dictates the speed with which instructions are processed. The faster the clock, the more operations can be executed every second.
Every processor is built of billions of transistors. From one generation to another (or from one year to the next, one could also say) manufacturers are able to fit more and more of them in the same tiny space. How densely the processor is packed with transistors - and, in turn, which generation it is - is described by the process technology used to create it.
In the case of notebooks, the main supplier of CPUs is Intel, and then, far behind, AMD. Their processors use the x86 architecture, same as the ones used in desktop computers.
Chromebooks, and sometimes (very rarely) MS Windows computers can also use processors typical for smartphones - built around the ARM architecture (Snapdragon, for example.)
For example right now, halfway through 2020, the most popular Intel processors are manufactured in the 10 or 14 nanometer process (Comet Lake - 10th generation of Intel Core processors, Ice Lake - 10th and 9th generation, and Coffee Lake - just the 9th generation.) You can still find some notebooks with the eight generation Kaby Lake, and Whiskey Lake processors.
From a user's point of view, process technology, which also translates into CPU generation, is very important. More often than not greater than it's clock speed, which is the thing most people take as an indicator of the computer's capabilities.
The generation of the processor
The newer the generation - which usually has to do with changing the process technology - the more transistors, and smaller energy consumption, and, in turn, better clock frequency. According to Intel, each consecutive generation is at least 15% more efficient than the previous one in the SySMark benchmark.
In practice, Intel processor's don't tell us which generation they are in their names, like Core i9, i7, i5, i3, but in the alphanumeric code following the name. For example, the Intel Core i7-1065G7 is a tenth generation processor (10xxx), the Core i7-8665U is the eighth (8xxx), and so on. The i3 to i9 codes tell us only which model in the given generation it is, where the lower the number we have, the less powerful processor we get.
Over the years, it became widely accepted that the higher the processor's clock rate, the better it is. And theoretically it's absolutely true: if the CPU processes instructions faster, it can finish the task in a shorter amount of time.
But in practice, the clock rate does not translate into the processor's capabilities one to one. Sometimes less GHz can mean longer battery life. It's also possible that a more recent, but technically slower processor will do better in tests.
We should also remember, that together with higher frequencies we get higher power consumption, which means the CPU will generate more heat, and we'll need a more potent cooling system to deal with it. It's especially important when talking about gaming computers.
In addition to the things we've already mentioned, there's one more thing that dictates how powerful our processor is - the number of cores it has. All current processors are multi-core. We could say that each core is an equivalent of a single processor. The more cores we've got (a multiple of 2), the more efficient the CPU is.
Doubling the core number doesn't mean we'll get twice the power. In order to process data in different cores, you need to separate them, which isn't as easy as it sounds. As a result, the difference in power between one and two cores is something around 50%.
Types of processors
Laptop CPUs can be placed into different categories, like:
- Economic, where the most important factor is the price of the CPU. Here we've got simple constructions, like: Intel Celeron, Pentium, AMD Series A, or the more efficient Intel Core i3.
- Low-voltage, which typically can be found in light ultrabooks, that have fantastic battery-life, but not only, as they are sometimes installed into more classic designs manufactured in 2020. Intel is the undisputed champion of this category, what with their Intel Cores with the letters U or Y in the name. Although AMD Ryzen 5 and 7s with the letter U may also be grouped here
- Gaming, which are very powerful, but it comes at the cost of shorter battery-life. Intel Cores with the letters H and HQ, and Ryzens 5/7 with the letter H are good examples.
- Extreme, which offer the best performance, and support overclocking (speeding up the clock rate.) They have the letters HK or K in their names.