Display Port not working

[Steve007]

Hi Everyone,

I recently purchased an HP Elitedesk 800 G3 Small Desktop Computer 64 bit Win 10 with 2 Display Ports.  Everything is working well except I cannot get the Display Ports to function correctly.

I'm trying to get 3 monitors to work. I have set up dual monitors many times before on other machines so I am familiar with the process.

Here is my setup;

2 identical Samsung monitors that have only HDMI inputs.

1 older HP monitor that has only a VGA input.

1 Radon card in the PCI slot which has an DVI output and an HDMI output.

I use the Radon card DVI output via adaptors to connect to the HP VGA monitor. This works fine.

I use the Radon card HDMI output to connect to one of the Samsung monitors. This works fine i.e., now I have dual extended monitors.

Now for the strange part.

I tried using a DP to HDMI  adaptor (to HDMI cable) so I could get the other Samsung monitor working, It is detected and works until I try to move e.g., a window onto it. Then it goes blank.

I looked in the BIOS and didn't see anything I thought was relevant. I did make the Radon card the VESA boot priority. I think I did try making the Intel onboard the priority once but then I had no display at all. I had to remote into it (long story) but got it working again with the Radon card driving 2 displays.

I appreciate any suggestions.

Thanks

Steve