A disk drive for storing data includes a drive housing, a storage disk that is rotatably coupled to the drive housing, a slider assembly positioned near the storage disk, and a drive circuitry. The slider assembly includes a head that interacts with the storage disk during a data transfer operation. The drive circuitry performs a performance test on the head at a first HtD spacing and at a second HtD spacing that is different than the first HtD spacing while the drive is operation. The slider assembly includes a slider mover that moves the head between the first HtD spacing and the second HtD spacing. The slider mover can move the head to the first HtD spacing during the data transfer operation if the result of the performance test is a first test result and the slider mover moves the head to the second HtD spacing during the data transfer operation if the result of the performance test is a second test result.