I've posted in this thread about issues I was having with my CX. With 120hz mode selected, my screen would always go black or flash random black screens when I was trying to play a game. 60hz would work fine, but 120hz was a mess. I had the Xbox plugged into HDMI port 2, which also has eArc/Arc labeled next to it. I removed the Xbox from that port and put it into port 3, and in that case 120hz mode was working just fine last night. I haven't tried this morning yet, but yea for me at least could I just have a faulty port on my TV or something?