In a time when mobile phones were thick and black and white, processors were single-core, and gigahertz seemed like an insurmountable bar (20 years ago), the only characteristic for comparing CPU power was clock speed. A decade later, the second important characteristic was the number of cores. Nowadays, a smartphone less than a centimeter thick contains more cores, and the clock frequency is higher than a simple PC of those years. Let's try to figure out what affects the processor clock speed.
The processor frequency affects the speed at which the processor transistors (and there are hundreds of millions of them inside the chip) switch. It is measured in the number of switches per second and is expressed in millions or billions of hertz (megahertz or gigahertz). One hertz is one switching of the processor transistors per second, therefore, one gigahertz is one billion such switching in the same time. For one switch, to put it simply, the kernel does one mathematical operation.
Following the usual logic, we can come to the conclusion that the higher the frequency, the faster the transistors in the cores switch, the sooner the problems are solved. That is why in the past, when the bulk of processors were essentially improved Intel x86, architectural differences were minimal, and it was clear that the higher the clock frequency, the faster the computation goes. But over time, everything changed.
Is it possible to compare the frequencies of different processors
In the 21st century, developers have taught their processors to process more than one instruction per clock cycle. Therefore, processors with the same clock rate, but based on different architectures, provide different levels of performance. Intel Core i5 2GHz and Qualcomm Snapdragon 625 2GHz are two different things. Although the second core has more, it will be weaker in difficult tasks. Therefore, the very frequency of different types of cores cannot be compared; it is also important to take into account the specific performance (the number of instruction executions per clock cycle).
By analogy with machines, the clock frequency is the speed in km / h, and the specific performance is the carrying capacity in kg. If a car (an ARM processor for a smartphone) and a dump truck (an x86 chip for a PC) are driving nearby, then at the same speed, a car will carry a couple of hundred kilos at a time, and a truck - several tons. If we talk about different types of cores specifically for smartphones (Cortex A53, Cortex A72, Qualcomm Kryo), then these are all cars, but with different capacities. Accordingly, the difference here will no longer be so huge, but also significant.
You can only compare the clock speeds of cores on the same architecture. For example, MediaTek MT6750 and Qualcomm Sanapdragon 625 each have 8 Cortex A53 cores. But at MTK their frequency is up to 1.5 GHz, and at Kualkomm - 2 GHz. Consequently, the second processor will run approximately 33% faster. But the Qualcomm Snapdragon 652, although it has a frequency of up to 1.8 GHz, is faster than the 625 model, since it uses more powerful Cortex A72 cores.
What gives a high processor frequency in a smartphone
As we have already found out, the higher the clock frequency, the faster the processor works. Consequently, the performance of a smartphone with a higher-frequency chipset will be higher. If one smartphone processor contains 4 Kryo cores at 2 GHz, and the second - 4 of the same Kryo cores at 3 GHz, then the second will be about 1.5 times faster. This will speed up the launch of applications, reduce turn-on time, allow faster processing of heavy sites in the browser, etc.
