Intel Xeon E5 2670 's Advantages
Released 2 years late
Newer PCIe version (3 vs 2)
Higher base frequency (2.6GHz vs 2GHz)
Larger L3 cache size (20MB vs 4MB)
More modern manufacturing process (32nm vs 45nm)
Intel Xeon E5503 's Advantages
Lower TDP (80W vs 115W)