AMD Ryzen 9 4900H 's Advantages
Higher base frequency (3.3GHz vs 2.4GHz)
Lower TDP (54W vs 55W)
AMD Ryzen 9 7940HX 's Advantages
Released 3 years and 10 months late
Higher specification of memory (5200 vs 4266)
Larger memory bandwidth (83.2GB/s vs 68.27GB/s)
Newer PCIe version (5.0 vs 3.0)
Larger L3 cache size (64MB vs 8MB)
More modern manufacturing process (5nm vs 7nm)