Thats no completely true memory is just like other parts cooler it runs sometimes you can push it further why do you thk some kits have larger heatsinks. Your desktop memory is just like the memory on say your video card heat and voltage can determine how far you can push it.
I've never heard of a memory fan, stabilizing an OC. If you can, show me proof, that attaching 2x40mm fans was able to stabilize an OC. I've never heard of such a thing. Sure, it's important to keep your ram cool, but attaching a fan, now stabilizes OC's?