Did yall know about the display port pin 20 thing?

Posted by ej1oo1@reddit | buildapc | View on Reddit | 14 comments

I built my dream computer last year and have loved it every day. I'm not a huge gamer but I wanted something beefy to last a good while. Got an rtx 3070 and a i7-12700k. Picked up an affordable 1440p monitor as part of the set up because I could run games at that res now if I wanted. The new monitor had display port and hdmi but my old, now second, monitor was hdmi only. With my 3070 only having 1 hdmi out I grabbed an Amazon basics display port cable to be connect to the new display.

Everything worked great. No build problems. I have been living the dream. But one quirk has been the monitor back light would turn on and off repeatedly when the pc was off or sleeping. This led to me just turning the monitor off when I was done for months. Today I decided to get to the bottom of this weirdness and after changing 1000 different power and monitor settings to no avail I found a thread saying it could be displayport pin #20 transmitting power. Apparently displayport has 20 pins but for most if not all cases the 20th pin should be left unconnected or else power can be transmitted when it should not be. This is sometimes not disconnected or wired wrong in cheap cables. Why the hell is this even a thing!? It sounded so dumb but I replaced my display port cable and it was indeed the problem. The monitor behaves now and life is good again. I figured I'd share my story if any of you are also wondering why your monitor does that weird thing.

Cheers fellow nerds

Edit: The cable that worked for those asking

Edit edit: also I lived in Texas for 6 years please excuse the unironic yall