I have a BenQ 144hz monitor with G-sync. I also have an El Gato HD60 for capturing the monitor which I am cloning the monitor to. Basically I've found when I am cloning the display with g-sync enabled it causes rapid black flickering on my BenQ monitor while the display is being cloned to my El Gato without any major issues. Initially I thought this was related to the higher refresh rate on my BenQ. I was surprised to discover it is only related to G-sync. Even if my Benq is on 60hz, the issue occurs with G-sync turned on. It's a minor inconvenience to be honest. I can just turn g-sync off and I don't see the issue even at 144hz. I only post this to see if anyone else has experienced/resolved this issue because I swear it didn't always happen. Not sure if it was switching to windows 10 or a nvidia driver that changed it or even some kind of fault in my hardware.