If I use the displayport cable the monitor starts up as expected when the PC is powered up. Maybe it was the hdmi cable, but I don't have another to test that at the moment. I've had this monitor many years, probably even with W8, and it has never started up with the hdmi cable but otherwise worked fine at full resolution.
For some years I’ve had my U2713H monitor connected to my XPS desktop via HDMI cable. I can never remember it ever starting up automatically when the pc is switched on, unlike any other monitor I’ve used. I always have to press the ‘on’ led at the bottom right of the panel to switch it on. Is there some setting I’ve missed to enable auto switch on?
XPS, U2713H not starting when PC starts