Nostalrius Begins - Quality wow vanilla realm (1.12)

Ive done BFD a day or two ago and I noticed that my fps went down from the usual 59 ( vsync) to 49 or 47 and it was stuck there. The game ran in a stutter, fragmented kind of way and I suppose it has to do with the dungeon because anywhere else outside it my game ran fine. I kind of suspect it has something to do with those blue lights like you see here https://youtu.be/A3lg7crf8ng?t=6m57s. It was playable but that stutter was very noticeable. Anyone else noticed it?

i5 4460, strix 960, win7 64, 6gb ram with all settings on high http://i.imgur.com/8aSV0lb.jpg I tried with sliders on low and result was the same