Guys, do not worry too much about software hacks, just solder in a new capacitor and you will be fine! I got the unused capacitor from Volker (many thanks btw!) to do that, and GPU switching is working again ever since (including Cinebench and External Screen). Still to be seen whether it reverts to faulty state later on: I had the GPU und Video ram replaced last year as this was the suggested fix then- only to find that it reverted some 2-3 months after the replacement to the faulty state again. Probably the heat of re-soldering temporarily "fixed" the capacitor or so. But anyway, I am optimistic now.
Many thanks to all who found out and have been testing these fixes. Our machines are far too good to be thrown away. And to be thrown away because of this ridiculously cheap capacitor - this is the sad part of the story. Some geeks fix it - the rest is going with workarounds or just buy new. Sad enough, Apple, that you never found out the real cause(s) for the GPU mess with the (but not only the) 2010 MBP 15, or did not bother to let us know, and that you never had the cool to just say, hey, it is just this crappy capacitor and we will fix this for you anytime for free. Because this is what I would expect from the most profitable company on earth selling really great products.
Many thanks to all who found out and have been testing these fixes. Our machines are far too good to be thrown away. And to be thrown away because of this ridiculously cheap capacitor - this is the sad part of the story. Some geeks fix it - the rest is going with workarounds or just buy new. Sad enough, Apple, that you never found out the real cause(s) for the GPU mess with the (but not only the) 2010 MBP 15, or did not bother to let us know, and that you never had the cool to just say, hey, it is just this crappy capacitor and we will fix this for you anytime for free. Because this is what I would expect from the most profitable company on earth selling really great products.