Intel Xeon E5 2643 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 (3.4GHz vs 2GHz)
Larger L3 cache size (20MB vs 4MB)
More modern manufacturing process (22nm vs 45nm)
Intel Xeon E5503 's Advantages
Lower TDP (80W vs 135W)