Here are two things I tried. seemed to help me.
http://www.esoui.com/downloads/info176-ESOToolbox.html
Try the add on above. Allows you to modify other graphics elements and to allow multiple threads.
This next one is tricky. ONLY download the Disable-CPU Core Parking Utility. its the "
Download application executable files ..." tiny link just above teh comments. there's other crap on the screen. Just down load the applicable file. we checked it and it's clean. This program allows you to unpark your cpus. for whatever reason, the game parks your cpus. if youwant to see if your cpus are parked, use the task manager and enter performance monitor. all 4 should be active.
http://www.coderbag.com/Programming-C/Disable-CPU-Core-Parking-Utility
I am no computer genius, just a dumb marketing guy, but my fps doesn't drop below 20 in major wabba fights. Hope these help.