Remove faulty color profiles
I had this problem with browsing file versions (the time machine universe). For me the trick was to remove bad color profiles. Somehow OSX added two color profiles to my system on its own initiative, but they were no match with my MBP. In the Displays preference pane I had three default profiles for my MBP display and a couple more for my other displays. Two profiles had the exact same name and clicking the second of those two was impossible. The selection auto-jumped to the top of the list.
In /Library/ColorSync/Profiles/Displays I had my regular profiles (including the good Color-LCD...icc) and the two faulty ICC's. Removing those 2 equally named profiles fixed the problem for me.
Now the graphics chips auto switch without visual difference.
I had this problem with browsing file versions (the time machine universe). For me the trick was to remove bad color profiles. Somehow OSX added two color profiles to my system on its own initiative, but they were no match with my MBP. In the Displays preference pane I had three default profiles for my MBP display and a couple more for my other displays. Two profiles had the exact same name and clicking the second of those two was impossible. The selection auto-jumped to the top of the list.
In /Library/ColorSync/Profiles/Displays I had my regular profiles (including the good Color-LCD...icc) and the two faulty ICC's. Removing those 2 equally named profiles fixed the problem for me.
Now the graphics chips auto switch without visual difference.