Intel Core i7 7800X 's Advantages
Lower TDP (140W vs 165W)
Intel Core i7 9800X 's Advantages
Released 1 years and 5 months late
Higher specification of memory (DDR4-2666 vs DDR4-2400)
Higher base frequency (3.8GHz vs 3.5GHz)
Larger L3 cache size (17MB vs 8MB)