Intel Xeon E3 1220 v3 's Advantages
Higher base frequency (3.1GHz vs 2.9GHz)
Lower TDP (80W vs 135W)
Intel Xeon E5 1681 v3 's Advantages
Released 1 years and 3 months late
Higher specification of memory (2133 vs 1600)
Larger L3 cache size (25MB vs 8MB)