Intel Core i5 9500 's Advantages
Integrated graphics card
Higher base frequency (3.0GHz vs 2.4GHz)
Intel Core i9 12900 's Advantages
Released 2 years and 9 months late
Higher specification of memory (DDR5-4800 vs DDR4-2666)
Larger memory bandwidth (76.8GB/s vs 41.6GB/s)
Newer PCIe version (5 vs 3.0)
Larger L3 cache size (30MB vs 9MB)
More modern manufacturing process (10nm vs 14nm)