The Intel Core Ultra 5 235F is the objective winner of this comparison, securing victories in eleven out of fourteen measured specifications. While the Intel Core i5-8400 maintains a 43% advantage in Max Turbo Power, the newer processor dominates in cache architecture. The most significant performance differentiator is the Intel Core Ultra 5 235F’s L2 Cache, which provides a 1233% improvement over the older model, representing the most impactful technical advantage between the two components.

Users prioritizing raw power efficiency and lower thermal output under peak loads should consider the Intel Core i5-8400 due to its superior Max Turbo Power rating. Conversely, those seeking a modern architecture with vastly expanded cache capacity for improved data handling should select the Intel Core Ultra 5 235F. This choice depends entirely on whether your specific computing needs favor the power management profile of the older unit or the substantial cache-based architectural gains of the newer one.