Example implementations relate to performance tests of capacitors. In some examples, a controller may comprise a processing resource to measure a change in voltage of a capacitor of a circuit in response to the controller entering a test mode, determine, based on the measured change in the voltage and an impedance of the circuit, a capacitance of the capacitor, compare the determined capacitance of the capacitor to a predetermined capacitance value, and determine, based on the comparison, a performance of the capacitor.