Intel Core i5 8400 's Advantages
Better graphics card performance
Higher specification of memory (DDR4-2666 vs DDR4-2400)
Larger memory bandwidth (41.6GB/s vs 38.4GB/s)
Newer PCIe version (3.0 vs 2.0)
Higher base frequency (2.8GHz vs 2.0GHz)
Intel Celeron J4025 's Advantages
Released 2 years and 1 months late
Lower TDP (10W vs 65W)