I currently have an i5-6500 and a GTX 1060 6GB, and I can barely keep 60 fps on lower settings (shadows low, lowest multisampling, low texture filtering) in Dalaran or 25m raids. My temps sit at around 20-35C, my GPU and CPU usage hover around 20-30%. Its as if WoW is refusing to use any more resources (or simply can't).
Things I have done/tried: Increased RAM capacity (from 2GB max), setting process affinity, setting texture cache size. Nothing really helps, and it just seems like WoTLK is an awfully optimized game or something is completely wrong with my install. For comparison I can run, for example, Overwatch on the highest settings, never drop below 60, and my temps never really get higher than 50-60C.
Has anyone figured out a magic formula for making WoW simply run better?
EDIT: Also worth mentioning, I don't play with new models.
Does it get much worse when increasing graphics settings? Have you tried disabling addons? Too many addons, wrong addon versions or messed up addon settings could cause it. Also WoW is heavy on CPU and most core, UI and addon functionality is done on a single thread so it can efficiently use only 1 CPU core. And what exactly you mean with "lower settings"? Are all other settings at max or also low?
Settings that seem to adversely affect my FPS. For example there is a noticeable difference with shadows on the lowest setting versus the highest. But again, I don't see how that is a thing considering my GPU is being barely used in the first place.
Some other settings are on max like texture resolution, and other minor settings. I have played around with it and checked which settings cause FPS decreases and it seems like shadows is the main one.
Important to note: Top right corner for temps and usage and stuff, bottom left corner for fps (38!).
Settings: Everything to max, except for: Shadow Quality (lowest), Texture Resolution (lowest), Texture Filtering (lowest), Player Textures (lowest), Full Screen Glow Effect (turned off), Multisampling (lowest), Vysnc On, Triple Buffering On, Windowed Mode (thought it could have been this but true fullscreen and borderless window made no difference).
Generally your FPS is not far from what you can expect in Dalaran but you should be getting that at max settings and not anything lower. I am getting similar results in the same location but on Icecrown with an older but similar CPU and much less powerful GPU. All settings at max except multisampling 1x and triple buffering off. The only specific thing I have done with my WoW client was changing the graphics engine it uses. Wotlk client has another graphics engine included that was experimental during this patch but was made the default engine in Cata. It might increase FPS a bit.
To enable it add this line to WTF/Config.wtf file:
d3d9ex makes my WoW run at 10 or less fps unfortunately (not sure whats wrong there). The other things from WoWTweakz seemed to have helped a little (hard to tell how much).
What is really odd is I have flawless well above 60 FPS when I am in a place with no players (eg. Silvermoon. Even with every graphic settings maxed out) then when in intensive 25 men raids or dalaran, it drops down to 30-40 ish which is really frustrating.
P.S. Also same result as the OP with d3d9ex command. FPS dropped down to 10.