I'm going to have to disagree with this theory... I read that article, but it just doesn't make any sense to me as to why a rad would dissipate more heat with lower flow. Lets consider what the temp of a rad with a low-flow would look like (assuming you straightened a rad out to make it easy to think) - water would have more time to cool down as it passes through the rad. Asuming flow from left to right (there should be a picture in your head now of a pipe with fins - a rad - going left to right with hot water going into the left side) - the left side of the rad would be hot, and the right side of the rad would be fairly close to ambient. As flow rate gets lower and lower, the temp of the rad on the right side would approach ambient, and so coolant leaving the rad would be closer to ambient temp. Coolant at ambient is good, but a rad in these circumstances is a BAD thing (I will get to why)
Consider a high-flow through this straight rad. The water flowing through the rad would not decrease in temp much (as we approach infinite flow, the temp wouldn't change at all), and so the entire rad surface would be hotter, and coolant leaving the other side would be hotter. Hot coolant going back into our system is not what we want - but really, this IS how we should be running our systems.
In the first case (low-flow), only the first part of the rad is above ambient temp, and is therefore actually doing work in removing heat from the system. The farther down the rad you move, the lower the delta temp to ambient, and the less heat that part of the rad is dissipating. In the high-flow case, the entire rad has a high delta-T to ambient, and will be working as efficiently as it can.
As for your water temp leaving the rad, it's irrelevent. We should not be concerned with the temp of a specific volume of water at some specific posistion within our cooling system, but with the overall amount of heat that our system is absorbing and dissipating. The higher the flow-rates, the bigger the delta-T's we will get in both the rad and the block, and the cooler our CPU's will run.
Getting back more into a real-life rad, when we start bending it around to fit into an acceptable area we also start introducing turbulence, which helps the water dissipate it's heat to the rad, and higher flows will help with this as well.
If you all have problems understanding what I'm picturing in my head, I can whip out MS Paint for a bit and see what I can make - just ask.
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