An explanation for hielko: The delta drops at the radiator with increased flow, but the chip gets better cooling due to the increased flow. The whole system needs to be considered. Temperatures actually do start to go back up after the flow gets so high, but it is because your more powerful pump is adding more heat into the system. There is a peak efficiency (depending on your specific system) between about 350 and 500 GPM according to published tests.
