Intel Core i3 6100 's Advantages
Higher base frequency (3.7GHz vs 3.1GHz)
Lower TDP (51W vs 65W)
Intel Core i9 9900 's Advantages
Released 3 years and 7 months late
Higher specification of memory (2666 vs 2133)
Larger memory bandwidth (41.6GB/s vs 34.1GB/s)
Larger L3 cache size (16MB vs 3MB)