Intel Core i5 6400 's Advantages
Integrated graphics card
Lower TDP (65W vs 140W)
Intel Core i7 6950X 's Advantages
Released 8 months late
Higher specification of memory (DDR4-2133 vs DDR4-2133)
Larger memory bandwidth (76.8GB/s vs 34.1GB/s)
Higher base frequency (3.0GHz vs 2.7GHz)
Larger L3 cache size (25MB vs 6MB)