Still haven't been able to undervolt or change the memory speed but I have better power numbers now.
Currently pulling 298W and the system is actually only 71W of that not the 110W as before. I've also found that poclbm is about 5% faster than diablo for me resulting in a new speed of 314Mh each.
Sidenote: I bought 2 different brand 7850's one Gigabyte http://www.newegg.com/Product/Product.aspx?Item=N82E16814125419
and one HIS http://www.newegg.com/Product/Product.aspx?Item=N82E16814161406
. The Gigabyte pulls 105W and the HIS pulls 122W. I'm assuming the Gigabyte's HSF design keeps it much cooler resulting in the fan spin much less
Not sure you're losing the power to a faster spinning fan, might be that as temperature increases, resistance increases. Ultimately you need to push a little more current to maintain voltage. I have no actual analytical data to support this for these circumstances, but as far as electronics theory goes...