AMD Ryzen 9 5900HS 's Advantages
Higher specification of memory (LPDDR4-4266 vs DDR5-5600)
Lower TDP (35W vs 35W)
AMD Ryzen 9 8940H 's Advantages
Released 3 years late
Larger memory bandwidth (89.6GB/s vs 51.2GB/s)
Newer PCIe version (4.0 vs 3.0)
Higher base frequency (4.0GHz vs 3.0GHz)
More modern manufacturing process (4nm vs 7nm)