A disk drive having a layer of lubricant on a disk surface, where an undesirable lubricant layer thickness modulation is reduced by varying /f during operation of the disk drive. Here is the angular velocity of the disk and f is a resonant frequency of a head assembly containing the head. In this manner, the amplitude of the lubricant thickness modulation is decreased, improving disk drive performance. The ratio /f is preferably varied by varying the disk angular velocity .