A method of ejecting drops of an ejectable liquid from a printhead is provided. The printhead has nozzles with bubble forming chambers, a heater element(s) disposed in the chambers configured for thermal contact with a bubble forming liquid and having bubble nucleation sections of smaller cross section than the rest of the heater element, and drive circuitry for controlling operation of the heater elements via electrodes, with parts of the drive circuitry disposed on opposing sides of the chambers. The method includes heating the heater elements by applying actuation energy of less than 500 nJ to form a gas bubble in the liquid that causes drop ejection from the nozzles and supplying the nozzle with a replacement volume of the liquid equivalent to the ejected drop. The bubble nucleation sections and the rest of the heater elements are co-planar and remain co-planar when heater elements are heated.