The Intel Core i5-12400 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 275% better than that of the Intel Core i7-9700K. This substantial improvement in cache capacity provides the primary edge for the newer processor, establishing it as the superior option across the majority of the evaluated performance metrics.

Users prioritizing modern architecture and the significant L2 cache advantage should choose the Intel Core i5-12400 for their build. Conversely, the Intel Core i7-9700K remains the appropriate selection for those who specifically require the 44% higher base clock speed provided by that unit. Selecting between these two components depends entirely on whether your specific workload benefits more from the increased cache capacity of the newer model or the higher base clock frequency of the older one.