Everything needed—monitor, peripherals, motherboard w/CPU and GPU, radiator, PSU, and so forth—is placed in a sealed, climate-controlled box at 25°C +/- 0.05 °C. Each radiator is connected by Koolance QD3 quick disconnects for easily changing the fans and radiator. The flow rate is held at 1 GPM constant flow rate. The CPU, an Intel Core i7-4770K at 4.6 GHz and 1.3 V, is held at a constant load using a custom Intel XTU profile, and the GPU, an EVGA GTX 780 Ti Classified under load from Unigine Heaven 4.0 at 1080p with extreme HD settings, is overclocked and overvolted in such a way that the total system power draw is 550 W as measured by an external power meter.
A near-constant heat load into the liquid loop by the addition of the CPU and GPU helps quickly achieve stable liquid-loop temperatures as measured by three separate in-line temperature sensors hooked up to an Aquacomputer Aquaero 6 XT. The tubing and fittings are insulated by a sleeve heater, but its heat function is not utilized. Every single measurement is done twice as a means of verification. Any possibility of running a fan outside of its static maximum RPM is minimized by as much as possible by using a comprehensive series of separate fans (Noiseblocker eLoop, B12-1 through B12-4) to cover a broad RPM range while minimizing fan speed variance and, thus, airflow. The results below are the ∆T (coolant temperature - ambient temperature) in degrees Celsius.
I have recently gone ahead and removed the 2200 RPM results because the trend is clearly against much higher speed fans, especially as there are now better performance/noise fans than the NB-eLoops used here. I was curious whether the 14 thicker tubes and shorter fins in a single stack were going to hold back the supposedly better cooling courtesy the "red copper" core. Turns out, this is not really all that much better than brass alloy radiators. If anything, performance is seen wanting at the lower to medium fan speeds and only picks up at the latter end, where it fares better perhaps at a point where airflow dynamics are no longer a concern and the material composition helps somewhat.