Intel Core i7 7500U Advantages
Higher base frequency (2.7GHz vs 1.7GHz)
Intel Core i7 8557U Advantages
Released 2 years and 11 months late
Better graphics card performance
Higher specification of memory (2400 vs 2133)
Larger memory bandwidth (37.5GB/s vs 34.1GB/s)
Larger L3 cache size (8MB vs 4MB)