Intel Core i5 1240U 's Advantages
Better graphics card performance
Higher specification of memory (5200 vs 4800)
Lower TDP (9W vs 55W)
Intel Core i9 12900HX 's Advantages
Newer PCIe version (5.0 vs 4.0)
Higher base frequency (2.3GHz vs 1.1GHz)
Larger L3 cache size (30MB vs 12MB)