Intel Xeon D 1581 's Advantages
Released 5 years and 11 months late
Higher specification of memory (4 vs 3)
Newer PCIe version (3 vs 2)
More modern manufacturing process (14nm vs 45nm)
Lower TDP (65W vs 80W)
Intel Xeon E5503 's Advantages
Higher base frequency (2GHz vs 1.8GHz)
Larger L3 cache size (4MB vs 1.5MB)