AMD Ryzen 9 4900HS 's Advantages
Higher specification of memory (LPDDR4X-4266 vs DDR5-5600)
Lower TDP (35W vs 35W)
AMD Ryzen 9 8940H 's Advantages
Released 3 years and 10 months late
Larger memory bandwidth (89.6GB/s vs 68.27GB/s)
Newer PCIe version (4.0 vs 3.0)
Higher base frequency (4.0GHz vs 3.0GHz)
Larger L3 cache size (16MB vs 8MB)
More modern manufacturing process (4nm vs 7nm)