Xeon E 2186M 's Advantages
Higher base frequency (2.9GHz vs 2.4GHz)
Lower TDP (45W vs 250W)
Xeon 6740E 's Advantages
Released 6 years and 2 months late
Higher specification of memory (6400 vs 2666)
Newer PCIe version (5 vs 3)
Larger L3 cache size (96MB vs 12MB)
More modern manufacturing process (5nm vs 14nm)