Intel Xeon E3 1558L v5 's Advantages
Released 6 years and 2 months late
Newer PCIe version (3 vs 2)
Larger L3 cache size (8MB vs 4MB)
More modern manufacturing process (14nm vs 45nm)
Lower TDP (45W vs 80W)
Intel Xeon E5503 's Advantages
Higher specification of memory (DDR3 vs DDR3)
Higher base frequency (2GHz vs 1.9GHz)