OptiPlex 3040 micro, dual monitors using HDMI and DP ports, DP connection unreliable
I've got an OptiPlex 3040 micro running Windows 10 64bit (came installed on the machine) and two monitors (Dell U2415, came as a pair) using extended display. One monitor has an HDMI-HDMI cable going into the computer's HDMI port, the other has a DisplayPort-DisplayPort cable going into the computer's DisplayPort port. (There is no VGA port installed on this machine)
Both monitors are on the correct setting for detecting what cable is plugged into them. Whichever monitor the DisplayPort cable is plugged into cuts out to a black screen with nothing on it multiple times an hour during normal computing (mostly email and web browsing). Not a steady flicker, just randomly goes black and randomly comes back on.
I uninstalled and reinstalled the drivers for the monitors, checked all the settings, ran the troubleshooter (no issues found), updated my graphics card driver (it was already the latest version), and nothing seems to be wrong there.
When I swapped the HDMI and DP cables to see if it was a cable issue or the physical monitor, the monitor that then had the DP cable plugged into it started to have the problem, whereas the other monitor (now plugged in via HDMI) had no problems. Originally there was a Mini DP-DP cable connecting one of the monitors and I thought maybe that was the issue, so I replaced it with a brand new DP-DP cable the other day. Still having issues with whichever monitor is connected via DP.
This computer is not even three months old. The physical cables aren't the issue and the physical monitors aren't the issue. Is there anything I can do to have the OptiPlex 3040 micro be able to have two Dell U2415 monitors simultaneously connected via Display Port and HDMI and have them work appropriately?
Thanks in advance! I've looked at other posts on here and on Windows' support forums but haven't found anything that works yet. Beginning to think the OptiPlex can't handle two monitors.