Intel Xeon E5503 's Advantages
Lower TDP (80W vs 105W)
Intel Xeon E5 2663 v3 's Advantages
Released 4 years and 6 months late
Higher specification of memory (2133 vs 3)
Newer PCIe version (3 vs 2)
Higher base frequency (2.8GHz vs 2GHz)
Larger L3 cache size (25MB vs 4MB)
More modern manufacturing process (22nm vs 45nm)