How is that? Which external screen do you run? Mine is 3840x1600 (38") and MBP 15.4 (with discrete AMD graphics) and fans never spin up just because it is hook

How is that? Which external screen do you run? Mine is 3840x1600 (38") and MBP 15.4 (with discrete AMD graphics) and fans never spin up just because it is hooked on external screen.