AMD Ryzen 9 5980HX 's Advantages
Higher specification of memory (LPDDR4-4266 vs DDR5-5200)
Higher base frequency (3.3GHz vs 2.3GHz)
Lower TDP (35W vs 55W)
AMD Ryzen 9 7945HX3D 's Advantages
Released 2 years and 6 months late
Larger memory bandwidth (83.2GB/s vs 51.2GB/s)
Newer PCIe version (5 vs 3.0)
Larger L3 cache size (128MB vs 16MB)