Opteron 1381 's Advantages
Higher specification of memory (1333 vs 3)
Higher base frequency (2.5GHz vs 1.8GHz)
Intel Xeon E5 2603 's Advantages
Released 2 years and 9 months late
Newer PCIe version (3 vs 2)
Larger L3 cache size (10MB vs 6MB)
More modern manufacturing process (32nm vs 45nm)
Lower TDP (80W vs 115W)