Starting us out in the thermal performance area is the C/W comparison. First up is C/W at a set flow rate. We use 1.6GPM as the baseline, but have also included 0.4GPM and 0.8GPM. In general, C/W will increase as flow rate decreases, meaning the water temperature will be higher with a lower flow rate when fan speed and heat in the loop remain constant. Yes, there is a point of diminishing returns, we do have pumps and pump heat dump to deal with… but 1GPM+ flow rates are easily attainable with today’s components. Also, be sure to look at the differences between flow rates. Some radiators do not handle low flow as well, just another factor to consider.
Looking at something a bit more applicable to choosing a radiator, watts dissipated. Here we calculate the watt dissipation of the radiator while maintaining a 10C Air to Water delta. Put another way, if your room temperature is 25C, how many watts can the radiator handle with the water temperature maintaining 35C. Surprisingly enough, many of the 120mm triples all stay grouped together within a few watts of each other until we progress upwards in fan speed, above 2300RPM is where the pack really starts to separate.