Opteron 6366 HE 's Advantages
Released 8 months late
Higher specification of memory (1866 vs 3)
Lower TDP (85W vs 95W)
Intel Xeon E5 2658 's Advantages
Newer PCIe version (3 vs 2)
Higher base frequency (2.1GHz vs 1.8GHz)
Larger L3 cache size (20MB vs 8MB)