Intel Core i7 7820X 's Advantages
Higher base frequency (3.6GHz vs 2.9GHz)
Lower TDP (140W vs 280W)
AMD Ryzen Threadripper 3990X 's Advantages
Released 2 years and 8 months late
Higher specification of memory (3200 vs 2666)
Larger memory bandwidth (95.37GB/s vs 79.47GB/s)
Newer PCIe version (4.0 vs 3.0)
Larger L3 cache size (128MB vs 11MB)
More modern manufacturing process (7nm vs 14nm)