hi ,
http://www.webpagetest.org/result/150326_8A_5700e82f8da465ecb8a456d8826bb273/
The same run is showing variable viewport sizes. At times it is showing a 3 column layout that happens when you have 1024x 768 and at times it shows the 4 column layout that shows 1366 x768 . What could be happening here?