The Intel Core i5-14500 is the objective winner of this comparison, securing victories in nine out of fourteen evaluated specifications. Its most significant technical advantage is the L2 cache, which is 1333% larger than that of the competing model. This substantial increase in cache capacity provides the primary performance edge for the newer processor, distinguishing it as the superior option across the majority of the measured hardware categories.

Users prioritizing raw processing efficiency and modern architecture should select the Intel Core i5-14500 to leverage its massive L2 cache advantage. Conversely, the Intel Core i5-8400 remains a viable choice for specific builds where power constraints are the primary concern, as it offers a 58% advantage in Max Turbo Power. Choose the former for general performance gains or the latter if your system requirements strictly favor lower power consumption profiles.