Aspects of the subject technology relate to control circuitry for displays. A display control circuitry includes a plurality of amplifiers to drive gamma signals for a pixel array having a plurality of pixels of a display and a segmented resistor string coupled to the plurality of amplifiers. The resistor string includes a plurality of resistor segments with a resistor segment being designed with a modified resistance to modify display performance parameters including at least one of a settling time of an associated gamma signal, a power supply rejection ratio (PSRR) of an amplifier of the plurality of amplifiers, or an output voltage offset of an amplifier of the plurality of amplifiers.