I was very upset when I got my new MacBook Pro 16' and when I connected my 27" DVI monitor it only worked at 1080p. I called several forums and was told I need this key. I contacted display support but they didn't know anything and offered to try it. All I can say is that it worked straight away and my monitor is now running at full resolution. .I only have 2 small issues. It seems a bit pricey but it saved me the price of a new monitor so it wasn't too bad. And it uses a USB-C connector as there is no pass-through hat.But it works and works well.
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