Intel Xeon E3 1275 's Advantages
Higher base frequency (3.4GHz vs 2.8GHz)
Lower TDP (95W vs 140W)
Intel Xeon E5 1603 v3 's Advantages
Released 3 years and 5 months late
Higher specification of memory (1866 vs 3)
Larger L3 cache size (10MB vs 8MB)
More modern manufacturing process (22nm vs 32nm)