The Intel Core i5-13400F is the objective winner of this comparison, securing victories in nine out of fourteen measured specifications. Its most significant technical advantage is the 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, establishing it as the superior option across the majority of the evaluated hardware metrics.

Users prioritizing high-performance computing should choose the Intel Core i5-13400F to leverage its massive L2 cache advantage. Conversely, the Intel Core i5-8400 remains a viable alternative for specific builds where power efficiency is the priority, as it maintains a 56% advantage in Max Turbo Power. Selecting between these two components depends on whether your system requirements favor the increased cache capacity of the newer model or the power profile of the older unit.