Intel Core i7 6700K 's Advantages
Higher base frequency (4.0GHz vs 3.4GHz)
Lower TDP (91W vs 150W)
Intel Core i9 12900KS 's Advantages
Released 6 years and 8 months late
Higher specification of memory (4800 vs 2133)
Larger memory bandwidth (76.8GB/s vs 34.1GB/s)
Newer PCIe version (5.0 vs 3.0)
Larger L3 cache size (30MB vs 8MB)
More modern manufacturing process (10nm vs 14nm)