In that motherboard, if they are dual channeling RAM (Increased bandwidth on supported RAM when using two)
put one in the green slot, and one in the blue slot, next to each other. If they do not support this feature, it won't make a difference in speed wherever you put them and so won't matter.
That seems like the way this board is working, otherwise it wouldn't be colour coded
Hope this helps
EDIT: Sorry Morpheus, I didn't see your post. Takes me ages to type it before I can refresh