RAM cooling can't help the IC's go past a certain speed w/o stuff like artifacting. It will help keep it cooler, but that in no way makes it easier to OC. The GPU is a different story.

Voltage mods on the RAM may help, but then you'll have to remember that the extra voltage adds heat. It may help gain a few extra MHz, but for the work done, I think a Vmod at that point is pretty moot.