Both are excellent for overclocking. As far as user experience in this area (8RDA+ vs 8RDA3+ in overclocking), you may find some threads related to this at <A HREF="http://aoaforums.com/forum/index.php?" target="_new">AOA Forums</A>. A lot of Epox motherboard users there.
<b><font color=blue>Oh, I can shed light on that ...</font color=blue></b>