AMD Ryzen 9 3900X 's Advantages
Newer PCIe version (4.0 vs 3.0)
Larger L3 cache size (64MB vs 8MB)
AMD Ryzen 3 5300G 's Advantages
Released 1 years and 9 months late
Integrated graphics card
Larger memory bandwidth (51.2GB/s vs 47.68GB/s)
Higher base frequency (4.0GHz vs 3.8GHz)
Lower TDP (65W vs 105W)