Xeon EC5509 's Advantages
Higher specification of memory (1066 vs 3)
Higher base frequency (2GHz vs 1.6GHz)
Larger L3 cache size (8MB vs 4MB)
Intel Xeon E5603 's Advantages
Released 1 years late
More modern manufacturing process (32nm vs 45nm)
Lower TDP (80W vs 85W)