Intel Xeon E5 2689 's Advantages
Higher specification of memory (1600 vs 3)
Larger L3 cache size (20MB vs 15MB)
Lower TDP (115W vs 130W)
Intel Xeon E5 2643 v2 's Advantages
Released 1 years and 6 months late
Higher base frequency (3.5GHz vs 2.6GHz)
More modern manufacturing process (22nm vs 32nm)