ok that's not normal for wow with that kind of machine , is this in raids or just idle in town , also you mention you have ddr3 1600mhz but how much ... 2gb, 3gb, 4gb ?
so my quick n dirty guide for troubleshooting wow
first ... try running wow with no add-ons copy your interface folder to the desktop this is better than just updating them all because sometimes things slip through the cracks .
restart wow completely see how it runs if this improves your fps slowly start introducing add-ons 1 by 1 by copying them out of you interface folder on the desktop to the new one that was created when you ran wow without it
leaving the big messy addons till las ( DBM , Xperl , recount etc etc) until you find your problems .
If there is no change without any add-ons then you need to look at your wow settings , blizzard changed a few options about last patch some of them can really muck the game up if they aren't right.
first of all look in your video options and make sure its set to good
make sure vertical sync is off
and that muti sampling is set to 1-2 ( you wont notice much difference past 2 )
shadow quality good
then in the advance tab , turn max forground fps to 100
Make sure the graphics API is set to direct x 11
( restart wow ) see if theres a differnce
if not something is wrong outside of your wow ... my pc has worse specs than yours and im sat in org with 100fps on those kind of settings .