Xeon 6980P 's Advantages
Released 9 years and 10 months late
Higher specification of memory (8800 vs 2133)
Newer PCIe version (5 vs 3)
Larger L3 cache size (504MB vs 25MB)
More modern manufacturing process (5nm vs 22nm)
Intel Xeon E5 2666 v3 's Advantages
Higher base frequency (2.9GHz vs 2GHz)
Lower TDP (135W vs 500W)