Intel Core i5 9400F 's Advantages
Higher specification of memory (2666 vs 2400)
Larger memory bandwidth (41.6GB/s vs 38.4GB/s)
Newer PCIe version (3.0 vs 2.0)
Higher base frequency (2.9GHz vs 2.0GHz)
Intel Celeron J4125 's Advantages
Released 10 months late
Integrated graphics card
Lower TDP (10W vs 65W)