Hi! I'm purchasing the 15'' Macbook Pro Mid 2015 model with the Intel Iris Pro graphics. The exact model number is MJLQ2KS/A. It's the basic 15'' Retina Model and not the more expensive one, with more storage etc. I'm wondering whether this machine will drive a external 4K 3840 x 2160 res monitor with 60hz refresh rate. Preferably the Dell or LG 27 inch IPS models. It doesn't have the secondary internal Radeon graphics. Will it still do the task with single stream transport? Thanks!