Intel Xeon E5 1691 v3 's Advantages
Higher base frequency (2.5GHz vs 2.1GHz)
Lower TDP (135W vs 500W)
Xeon 6979P 's Advantages
Released 10 years late
Higher specification of memory (8800 vs 2133)
Newer PCIe version (5 vs 3)
Larger L3 cache size (504MB vs 35MB)
More modern manufacturing process (5nm vs 22nm)