Why is the processor frequency in stores different from the frequency in the tests?

Question

Processors

The Intel Core i5-8400 in the market shows that the frequency is 2800 MHz, I look at the tests, it costs 3.4-3.8 GHz everywhere. Despite the fact that all as one do not indicate that their processor belongs to the K series (although they usually indicate). Is it some special 8400 they have or I don’t know how to search?

Answer 1

The maximum frequency of 8400 is 4 GHz - with a single-threaded load (1 core). For example, you install a game, the installer is single-threaded, i3 will count on 1 core at a locked frequency, and i5 will accelerate to 4 GHz and overtake it by a lot. On 2 loaded cores, it will reset the frequency to 3.6, on 4 cores to 3.2, and on all 6 it will work at its native 2.8 GHz. That's the whole point of turbo boost - if the load is not optimized for multithreading - give it a very fast core, thereby speeding it up.
So 2.8 is the nominal frequency at 100% load on all cores. Turbo boost frequencies indicate the acceleration of non-optimized applications and are not used in combat mode.