The Intel Core i5-12400 is the objective winner of this comparison, securing victories in eight of the fourteen evaluated specifications. Its most significant technical advantage is the L2 cache, which is 400% larger than that found in the Intel Core i7-8700K. This substantial increase in cache capacity provides the primary performance edge for the newer processor, effectively outpacing the older model across the majority of the measured hardware metrics.

Users prioritizing modern architecture and the efficiency of a significantly larger L2 cache should choose the Intel Core i5-12400. Conversely, the Intel Core i7-8700K remains a viable option for those who specifically require a higher base clock speed, where it maintains a 48% advantage over the newer chip. Select the former for general architectural improvements or the latter if your specific workload relies heavily on the higher base frequency provided by the older hardware.