Intel Xeon E5 1681 v3 's Advantages
Released 2 years and 6 months late
Higher specification of memory (2133 vs 3)
Higher base frequency (2.9GHz vs 2.4GHz)
Larger L3 cache size (25MB vs 20MB)
More modern manufacturing process (22nm vs 32nm)
Intel Xeon E5 2665 's Advantages
Lower TDP (115W vs 135W)