Opteron 8218 (F3) 's Advantages
Higher base frequency (2.6GHz vs 2.5GHz)
Lower TDP (95W vs 115W)
Opteron 1381 's Advantages
Released 2 years and 10 months late
Higher specification of memory (1333 vs 667)
Newer PCIe version (2 vs 1)
More modern manufacturing process (45nm vs 90nm)