Intel Xeon D 1581 's Advantages
Released 7 years and 5 months late
Higher specification of memory (DDR3 vs DDR2)
Newer PCIe version (3 vs 2)
More modern manufacturing process (14nm vs 45nm)
Lower TDP (65W vs 150W)
Intel Xeon X5492 's Advantages
Higher base frequency (3.4GHz vs 1.8GHz)