AMD Ryzen 9 3900X 's Advantages
Higher specification of memory (3200 vs 2933)
Larger memory bandwidth (47.68GB/s vs 43.71GB/s)
Newer PCIe version (4.0 vs 3.0)
Higher base frequency (3.8GHz vs 3.7GHz)
Larger L3 cache size (64MB vs 4MB)
More modern manufacturing process (7nm vs 12nm)
AMD Ryzen 5 3400G 's Advantages
Integrated graphics card
Lower TDP (65W vs 105W)