A magnetic memory which in some embodiments compares compressed fault maps is disclosed. In one embodiment, the magnetic memory may include at least two magnetic memory cells which are configured to store data. The magnetic memory includes a control system configured to periodically obtain parametric values from the magnetic memory cells and generate a corresponding compressed fault map using the parametric values. In some embodiments, at least one of the compressed fault maps is compared to a previous one of the compressed fault maps, and an indication is provided if there are differences.
