Very Poor FPS in WOTLK

Sorry if this is the wrong place to post this,

So I have extremely poor performance throughout every zone (around 20 fps); however my system should easily be able to handle this game fluidly. I checked my CPU usage and noticed that one core is ~100% usage while the others are not being utilized. GPU utilization is ~50%. Ive looked around and WOW indeed only uses a single processor core. Is everyone experiencing this kind of fps? Is there some kind of work-around?

No graphics settings seems to be making much of an impact: the difference between low and ultra presets is like an average of 2 fps. I play at a res of 3440x1440, but even playing on lower resolutions only slightly increases performance. Windowed vs Full-screen also doesn't seem to make a difference.

Relevant System Specs -
Fury X
i7 4770k

I am thinking now that the slowness might be attributed to the hyper-threading on my CPU. Did anyone else have a similar experience? Thanks for any help.