The AMD Ryzen 7 3700X is the objective winner of this comparison, securing more individual specification victories than its counterpart. Its most significant advantage is a 38% better thermal design power, which indicates a more efficient power profile for your system. While the AMD Ryzen 7 5800X3D falls behind in the total count of winning specifications, it maintains a substantial lead in memory architecture, specifically offering a 200% larger L3 cache capacity.

Choose the AMD Ryzen 7 3700X if your primary goal is power efficiency and a lower thermal footprint for your build. Conversely, select the AMD Ryzen 7 5800X3D if your specific computing needs prioritize the massive L3 cache advantage provided by that architecture. These two processors cater to different priorities, so your decision should rest on whether you value the superior power efficiency of the former or the expanded cache capacity of the latter.