The processor is the most important part in an electronic device, including cell phones here, because it is the one that is responsible for all data processing and has a direct influence on things such as the speed or speed of the cell phone, battery life, temperature of the equipment (which directly influences the operating speed) and image processing (quality of photos or videos taken by a cell phone)..
Expensive cell phone vs. cheap
The processor is one of the reasons why a high-end cell phone is superior to a low-end one and also more expensive. It is not difficult to deduce that a $ 1000 cell phone has a much better processor than a $ 200 cell phone, regardless of the brand that uses one or the other, be it Snapdragon, Exynos, Dimensity, etc. These CPU brands are manufactured in different ranges, and when we talk about two different ranges of processors, it has little to do with which company they are, since there will be a great difference between one and the other.
For example, I have seen how a brand like Qualcomm Snapdragon is usually quite appreciated and it is rejected when listening to any other CPU brand like Mediatek. However, while this may be acceptable today when it comes to the same range of processors, do not think that Qualcomm is always better than Mediatek or the rest. It all depends on the context. To clarify, I have to make an extremely obvious comparison like the following. A high-end processor from Mediatek, such as the Dimensity 1200 (2021) that comes in the Xiaomi Mi 11T, Redmi K40 or OnePlus Nord is quietly about five times higher / better than the low-end Snapdragon 480 (2021) from Qualcomm and that comes in the Motorola Moto G50..
Same range, different processor brand
The above may seem quite obvious, but it is not so obvious when talking about the same range of processors in a particular cell phone model, such as the Samsung Galaxy S21 Ultra. Perhaps a person who buys this cell phone in Spain or Latin America thinks they are buying the same Samsung Galaxy S21 Ultra that is sold in the United States. Finally you pay 1000 dollars here or there (or a similar value) and we are talking about the same cell phone model, so they should be the same. Unfortunately, this is not the case, since this cell phone comes with a different processor in these regions, specifically the Samsung Exynos 2100 in Europe / Latin America and the Qualcomm Snapdragon 888 in the United States. Although both processors are high-end and the difference is no longer as abysmal and noticeable as in the previous example, it does exist.
Photo taken by two Samsung Galaxy S21 Ultra with different processor: Qualcomm Snapdragon (left) vs. Samsung Exynos (right) Source: PhoneArena In this particular example, leaving aside the difference between autonomy and speed that exists between one processor and another, which is not a big deal either, the perhaps most interesting part is the difference in image quality. As you can see in the image above, the Exynos 2100 version of the Samsung Galaxy S21 Ultra (right) takes lower quality photos in low light conditions, darker compared to what you have with the Snapdragon 888 (left). Maybe a 5 or 10% difference, nothing radical, but there it is. In this case we are talking about a slight superiority of Qualcomm over Samsung, which has been shortened in recent years, but that was not always the case. At the time, Samsung Exynos processors were the most appreciated within the Android segment..
Is Snapdragon, Exynos or Mediatek better?
Obviously, to talk about speed, autonomy and quality of photos or video you can not only talk about the processor. The battery size, the quality of the photo sensor or the RAM memory also have a direct influence here. They are factors that must be evaluated at the same time when looking for a cell phone. However, the processor influences all these aspects directly. When choosing between cell phones of different ranges, things are easy, since the difference will always be marked between one equipment and another, regardless of which company is the processor of one and the other. If we talk about cell phones within the same price range, the difference will no longer be so marked. Anyway, if you are thorough and looking for the best, you can get an idea with the processor benchmarks ( this page gives you the numbers ), as well as with the reviews, which are finally the ones that will give you a real and practical overview of the differences.
References : PhoneArena
WatchDog, a real-time CPU usage monitor for Android
Samsung Galaxy models and their differences: Note, S, A, M, J
10 solutions for a SLOW cell phone that gets stuck