Intel Core i5 6600K Advantages
Integrated graphics card
Higher base frequency (3.5GHz vs 2.9GHz)
Lower TDP (91W vs 140W)
Intel Core i9 7920X Advantages
Released 2 years late
Higher specification of memory (2666 vs 2133)
Larger memory bandwidth (85GB/s vs 34.1GB/s)
Larger L3 cache size (17MB vs 6MB)