Intel Xeon E5503 's Advantages
Lower TDP (80W vs 95W)
Intel Xeon E5 2630 's Advantages
Released 2 years late
Newer PCIe version (3 vs 2)
Higher base frequency (2.3GHz vs 2GHz)
Larger L3 cache size (15MB vs 4MB)
More modern manufacturing process (32nm vs 45nm)