Intel Core i3 7100 's Advantages
Better graphics card performance
Higher base frequency (3.9GHz vs 3.1GHz)
Lower TDP (51W vs 65W)
Intel Core i9 9900 's Advantages
Released 2 years and 3 months late
Higher specification of memory (2666 vs 2400)
Larger memory bandwidth (41.6GB/s vs 35.76GB/s)
Larger L3 cache size (16MB vs 3MB)