You may have to tone down what settings you change. If you set them all tot super high and have your other wow's open, uppon changing your games may crash when attempting to change windows and adjust the video settings. Try starting at medium and go from there. I always like the max view distance and particle density myself.
I'm about to get to work on my setup for this now, its been a while since I initially wanted to set this up. It will take some playing with to get it right, but it'll get me a little more edumicated with ISBoxer

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