The Intel Core i5-14400F is the objective winner of this comparison, securing victories in nine out of fourteen measured specifications. Its most significant technical advantage is its L2 cache, which is 533% larger than that of the Intel Core i5-8400. This substantial increase in cache capacity provides the primary performance edge for the newer processor, making it the superior choice for users prioritizing modern architectural improvements and increased data handling efficiency.

Users should select the Intel Core i5-14400F if they require the enhanced L2 cache for improved processing capabilities. Conversely, the Intel Core i5-8400 remains a viable option for those specifically seeking a lower Max Turbo Power, as it holds a 56% advantage in that category. Choosing between these two components depends on whether your priority is the significantly higher cache capacity of the newer model or the lower power consumption profile of the older unit.