Opteron 2222 's Advantages
Higher base frequency (3GHz vs 2.666GHz)
Lower TDP (95W vs 130W)
Xeon X7542 's Advantages
Released 2 years and 7 months late
Higher specification of memory (1333 vs 2)
Newer PCIe version (2 vs 1)
More modern manufacturing process (45nm vs 90nm)