Hi, Overall, I've been quite pleased with my new 15" rMBP (mid-2014 base model). The screen is beautiful and the machine is snappy. However, I was just using Google Maps and the experience is as painfully laggy as it was on my old machine. I noticed when the Google Maps interface changed, in the past year or so, it got really painful to use on my old computer. Street view is now so much slower and it takes longer for the graphics to render. Scarcely anything causes my new rMBP to break a sweat but Google Maps does. My machine heats to 80 degrees C. Could the Iris Pro graphics not be up to snuff? Is the experience quite better with the 750m?