This Counter32 is the cumulative count of memory-mirroring errors detected between sockets (inter-socket) for this CPU, a RAS feature that duplicates memory contents across sockets for resiliency. An admin watches this counter because a rising count signals memory-mirroring hardware issues affecting cross-socket redundancy on that specific server. For example, a steadily climbing MirroringInterSockErrors count on one CPU, while its sibling socket stays at zero, would point support toward a mirroring-path problem specific to that processor.