Yeah, I havent really messed with it either to tell the truth...but I just don't have good enough cooling (a neccessity)
So...hmm... I have no answer to your question what so ever I'm afraid
...whatever it is, it must be the RAM chip in some way or your motherboard not liking to switch to it (I suggest RAM) and so i'm afraid your missing out, like spending a bit more to get dual channel and you can't even use it
Check in your motherboard manual...some motherboards are very tetchy about what RAM chips go in where when in Dual Channel, so its good to check first.
Any chance you can replace the RAM to see if this is the problem if the above doesn't work?