Click picture to zoom in - Higher is better

In the above curves, we show the heat dissipation performance of the MCR120-QP with our Delta M class 120mm fan running at 12, 7 and 5 Volt. For additional reference, we also show: a high-flow/high noise Delta HE class fan, a low flow/low noise Papst fan, the MCR120-Old with our Delta M fan as a yellow curve, and Noise levels for all fans tested.

Knowing that typical Swiftech systems operate in the 1.25 GPM range, several observations can be made from the above:

With the same Medium output Delta M fan, the MCR120-QP dissipates ~5% more heat than the earlier version, across all "real-life" flow rates.
There are little gains to be made from increasing the flow rates over 2~2.5 GPM.
For extreme low noise applications, a "specialty " fan such as the tested Papst delivers comparatively better performance than an under-volted fan such as the Delta M. Nonetheless, the Delta at 7 Volts offers whisper-quiet operations while supporting the power range of most desktop CPU's on the market (120W) and maintaining only a 10°C temperature rise of the coolant over ambient air. We also see that the same is not true when the fan operates at 5v. At this low voltage, we can predict from the curve that any heat load in excess of 75Watts will cause the coolant temperature to rise above 10°C. The next set of curves will then be useful to calculate what the rise will be.

Click picture to zoom in - Lower is better

The above curves are very similar to waterblock C/W data and can be interpreted in the same fashion. They will allow users to estimate the temperature rise of the water in the circuit, based on the coolant flow rate.

We can use the curve of the Delta 1212M running at 5 volt to illustrate how to calculate the coolant temperature rise over ambient air. Assuming for example a Swiftech loop flowing 1.25 GPM, and a CPU heat load of 100 Watts, at 5v the C/W of the radiator would be 0.13, and the coolant temperature rise above ambient would be 100 Watts x 0.13 = 13°C.