Intel Xeon E5 1691 v3 's Advantages
Higher base frequency (2.5GHz vs 2.2GHz)
Larger L3 cache size (35MB vs 30MB)
Xeon E5 2650 v4 's Advantages
Released 1 years and 6 months late
More modern manufacturing process (14nm vs 22nm)
Lower TDP (105W vs 135W)