Embodiments of the present invention relate to systems, methods, and computer readable media for calibrating storage devices such as hard drives. A testing system is connected to a group of storage devices that are being prepared for release and eventual sale. Alternately, a storage device may be connected to an end-user system for which it is in use. The storage devices are tested for head instability. A lower frequency test pattern is performed, which induces a stronger magnetic field. A measurement of servo gain control is taken while reading from a disk and compared to a baseline for servo gain control. If the variance is larger than a predetermined amount, then the read/write head is determined to be unstable.