You're replacing the radiator fan, not the fan in the graphics card shroud, right? I'm pretty sure that fan does not plug into the card itself, but rather onto a motherboard fan connector. If I'm right, then the graphics card should be completely unaffected by changing the fan on the radiator.
However, if the fan does connect to the graphics card, then it might have some specific properties to run, and another fan may not work properly. I doubt it would cause PCB damage, though. Worst case, you can disconnect the fan from the graphics card, connect the new fan to the motherboard, and just run the new fan at a constant RPM or get some fan management software to dial it up or down as needed.