Hi, I've just taken delivery of a 2015 - 15.4 rmpb - 1TB - dGPU etc Its all great, however the first thing I tried to do is open a simple .pdf document and zoom in and out. The thing stutters and the beach ball comes up before jumping to the zoomed in or out position. This is a bit pathetic for a computer of this supposed power? My 2009 didn't even do that ! (OK its a retina screen ... ) (This is with the dpgu on) Any thoughts would be great.