Per Apple the Max on the backlit is 8mb, 9 on the non-backlit. So unless you can get it to run with 10MB or more then I am not sure how the myth part plays into this. The stacked boards are no secret either.
Oh.. I was told you could only go up to 4 on the backlit... and I've got 7mb in there.. So I was just going on that 4MB max I was told... I just never seen one of these cards.. that's why I was flipping about it..