ok weird -
First, in the list of monitors, i have Primary/Monitor 1/Monitor 2. Doesn't seem to change anything except which screen it selects when I start the game (primary = monitor1)
I've tried DX9 or 11, same behavior.

second, i don't seem to have the "High Performance nVidia Processor" option in my Nvidia settings, but i'll try and adjust others for WoW specifically to see if it makes an difference.

now for the interesting bit: If I configure WoW to be windowed as 1366x768 (the resolution of the laptop screen) then i can drag the wow window from one screen to the other.
While playing, and therefore not changing any video settings:
- When i drag wow towards the laptop screen the fps climbs to 60.0 within a second.
- when I drag wow towards the external screen, the fps decreases slowly to 30.0.
- if the screen is halfway across the screens, the fps is 30ish
I don't get it.

I also dont understand where those limitations are since they really indicate 30.0 or 60.0 (Dot zero) and vary very little.
the config.wtf file has
SET maxFPS "95"
SET maxFPSBk "25"
and the fps does indeed go to 25 when wow is not in the foreground. while typing this post for example.

Any input welcome.
cheers,
Zub