I have a new 08G-P4-2182-KR in a Gigabyte Z390 Aorus Master with 19-9900K. I was using an old GTX 960 that worked fine in the build, so my assumption is that the board, memory, and chip are stable (not over clocked).  When I installed the new RTX 2080 I have it connected to 2 Dell U2718Q monitors thru displayPort.  It will work sometimes, other times it will just stop sending a signal to the monitors (monitors say no signal on DP - cables are good quality and never had issue previously).  It even happens sometimes when in the BIOS.  The temperatures looked fine when I could see them (HWINFO64 reported mid 30s with 1 monitor, 2 kicked it up 5+ degrees).  Thoughts?  Any know issues?  Return to store and try another one?

Pull the Power Cord from your "Dell U2718Q monitors" and count to 10 and plug back in the Power Cord and they will wake up.
Plug the Power Cables back in the Order of your Monitors you have setup in the NVIDIA Control Panel.
Also make sure you are not using Dell's bypass ports unless you have them setup and are using them.

bcavnaugh
Pull the Power Cord from your "Dell U2718Q monitors" and count to 10 and plug back in the Power Cord and they will wake up.
Plug the Power Cables back in the Order of your Monitors you have setup in the NVIDIA Control Panel.
Also make sure you are not using Dell's bypass ports unless you have them setup and are using them.

The power trick I know well, but not any help here.  No bypass port in use.  Currently just trying to get one screen to work, so I have tried both DP and HDMI to no avail...  Any other suggestions?

black screen of 2080/2080ti. known issue. It's a rma. I had one as well. Mouse and keyboard would lose led control. Ican get into safe mode with onboard graphics card but as soon as trying to install nvidia driver the screen turns black and no response from keyboard/mouse. Had to hard reset pc to restart from case. There are some other issues can cause this. But there are some cases the card is faulty itself so you have to rma.