Disclosed is an inkjet print cartridge including an ink reservoir; a substrate having a plurality of individual ink firing chambers with an ink firing element in each chamber along a top surface of said substrate and having a first outer edge along a periphery of substrate; the first outer edge being in close proximity to the ink firing chambers. The ink firing chambers are arranged in a first chamber array and a second chamber array and with the firing chambers spaced so as to provide 600 dots per inch printing. An ink channel connects the reservoir with the ink firing chambers, the channel including a primary channel connected at a first end with the reservoir and at a second end to a secondary channel; the primary channel allowing ink to flow from the ink reservoir, around the first outer edge of the substrate to the secondary channel along the top surface of the substrate so as to be proximate to the ink firing chambers. A separate inlet passage defined by a barrier layer for each firing chamber connecting the secondary channel with the firing chamber for allowing high frequency refill of the firing chamber. The separate inlet passage for each firing chamber having peninsulas and pinch points formed in the barrier layer to prevent cross-talk and overshoot during high frequency operation. A group of the firing chambers in adjacent relationship forming a primitive in which only one firing chamber in said primitive is activated at a time. A first circuit on said substrate connect to the firing elements and a second circuit on the cartridge connect to the first circuit, for transmitting firing signals to the ink firing elements at a frequency greater than 9 kHz. The preferred configuration of the nozzle member, ink channels, and vaporization chambers allows a printing resolution of 600 dpi and a firing rate of greater than 9 kHz.