Even with your ram underclocked and under utilized, I would strongly suggest ensuring that the rest of the card (especially the power regulation circuitry) gets some
cooling. If you have one of those side panel intake fans blowing over the PCIe slots then I wouldn't worry about it too much but otherwise it might be time to start case modding
The thing that make me cringe about the H50 and H70 (and to a lesser extent other pump on waterblock combo kits) is the mass of all that stuff hanging from a videocard not designed to hold up much weight. Obviously this is only a problem if the system is housed in a tower case.