The present disclosure provides methods and apparatus useful in depositing materials on batches of microfeature workpieces. One implementation provides a method in which a quantity of a first precursor gas is introduced to an enclosure at a first enclosure pressure. The pressure within the enclosure is reduced to a second enclosure pressure while introducing a purge gas at a first flow rate. The second enclosure pressure may approach or be equal to a steady-state base pressure of the processing system at the first flow rate. After reducing the pressure, the purge gas flow may be increased to a second flow rate and the enclosure pressure may be increased to a third enclosure pressure. Thereafter, a flow of a second precursor gas may be introduced with a pressure within the enclosure at a fourth enclosure pressure; the third enclosure pressure is desirably within about 10 percent of the fourth enclosure pressure.