The AMD Ryzen 7 5700X wins in 10 out of 14 comparable specs, with 2 ties. Its biggest advantage is L3 Cache (256% better).
Core i5-8400 wins in 2 specs (MSRP: 39% better).
Recommendation
Choose Ryzen 7 5700X if you want the best overall performance — especially l3 cache.
Choose Core i5-8400 if msrp matters more to you.
