Intel Xeon E5 2643 v2 's Advantages
Higher base frequency (3.5GHz vs 2.4GHz)
Larger L3 cache size (15MB vs 1.5MB)
Intel Xeon D 1521 's Advantages
Released 2 years and 2 months late
Higher specification of memory (4 vs 3)
More modern manufacturing process (14nm vs 22nm)
Lower TDP (45W vs 130W)