Xeon E5530 's Advantages
Higher specification of memory (1066 vs 4)
Higher base frequency (2.4GHz vs 2.2GHz)
Larger L3 cache size (8MB vs 1.5MB)
Intel Xeon D 1520 's Advantages
Released 6 years late
Newer PCIe version (3 vs 2)
More modern manufacturing process (14nm vs 45nm)
Lower TDP (45W vs 80W)