I have had this Elitebook 840 G3 about two weeks. When I am using the laptop by itself, the screen flickers and goes black. This occurs randomly and only lasts a few seconds (maybe about once or twice per hour). When an additional monitor is attached directly to the laptop, either through the HP Displayport or the VGA port, then both screens flicker and the external monitor will actually go black for a few seconds at a time. When docked in a slim docking station, the same problem occurs with monitors connected through the dock as with those directly connected.
I first upgraded all the drivers using the HP Support Assistant. Then the flickering still continued and I upgraded the drivers for the Intel HD Graphics 520 directly from Intel. The system is currently on driver version 20.19.15.4483 dated 7/1/2016. This laptop has an intel i5-6300U processor, 8G RAM, and is on Windows 10 Enterprise with all the latest updates applied.
I do not think this is a hardware issue, because:
1) There are 2 others that work with me that also just received new 840 G3 notebooks that are having exactly the same problem
2) It happens when using the laptop alone, when using the laptop with monitors directly connected, and when using the laptop monitors connected through a slim dock
3) When the flickering occurs and the external monitors go black, the open windows on the screen do not move back to the laptop screen unless you unplug the monitor or the slimdock
4) And if you wait long enough (up to 10+ seconds), the flickering stops and all the screens appear normal again.
