The Intel Core Ultra 9 285KF is the objective winner of this comparison, securing victory in twelve out of sixteen measured specifications. Its most significant technical advantage over the Intel Core i5-12400 is its L2 cache capacity, which is 433% larger. This substantial increase in cache memory provides the superior processor with a clear lead in architectural efficiency and data handling capabilities compared to the older model.

Users prioritizing high-end technical specifications and maximum cache capacity should select the Intel Core Ultra 9 285KF for their builds. Conversely, the Intel Core i5-12400 remains the logical choice for budget-conscious buyers, as it holds a 67% advantage in MSRP. Those who do not require the advanced cache architecture of the newer chip can leverage the significant cost savings offered by the more affordable option.