I'm very happy that the Gemini performs well at that low of a flow rate, but I really believe that it would perform even better at a higher flow rate. As pHaestus points out, increased flow rate will help a waterblock perform in several ways.
1. Increased velocity causes the boundary layer to thin out, which means that the heat has less distance to travel before it can get "carried away" by the moving water.
2. Increased velocity means that the water in the block is more constantly refreshed with the cooler incoming water.
3. Increased velocity causes the water within the block to "mix up" more (similar but not the same as the boundary layer). This is "turbulent flow" versus "laminar flow".
On the other hand, if the water moves too fast, it could hit the copper so hard that it etches it. Somehow, I doubt that our puny mag-drive pumps are that powerful.
