Erm. I don't think it's side by side... I've never seen that before, it doesn't make sense. I mean, why would they make the slots black and yellow? I mean, I very well could be wrong, I've just never seen that before. Double check that and make sure man.
edit: Awesome build! I'll be ordering an e6600 in the summer time, after Intel drops their prices
edit2: Check this picture out: http://www.phoronix.net/image.php?id...it_p5b_sys_lrg
Once again, double check and make sure those are in the right slots.