Test this...

* Turn the Optiplex 7010 SFF and all monitors off
* Disconnect all monitor cabling from the Optiplex 7010 SFF
* Connect one monitor to the Optiplex 7010 SFF onboard VGA out port
* Turn the monitor on, then the Optiplex 7010 SFF
* Press F2 to enter the BIOS
* Go to Video
* Check Enable Multi-Display
* Exit the BIOS saving change
* Once back into Windows, turn the Optiplex 7010 SFF off
* Connect a second monitor to the Optiplex 7010 SFF DP out port
* Turn the second monitor on, then the Optiplex 7010 SFF

What happens? Does the second DP monitor appear in Windows?

Same issue, but when I go to VIDEO, there is no multidisplay option

Any solution ?

Have the same problem

"The onboard VGA works, but the DP simply do not"

when posting about DP or VGA, always say what is in the PCI-e slots NOW.

you did not.

why not first tell all you have there

it must be 2 DP monitors, right? 

my guess is you have an old VGA only monitor there, none stated and windows 10 64bit?

do not connect 1 monitor iGPU port then other to PCI-e card GPU ports. (crossed over)

use the card only

or not, only,.

in BIOS click video see AUTO there,  and is default. and when you put the card in the iGPU goes off line.

do not hotswap any thing inside  any  PC. (ok?)

Onboard DP or any other ports on CARD will not work if the INTEL Display driver/Radeon Driver is not installed.  Radeon Drivers are also now legacy so they must be manually installed for HD2000 to HD8000 Series.  Chipset drivers are no longer optional.

The Microsoft VGA driver does not support multi display.

All of the drivers are in a single cab file.

You download the cab and move to the my documents folder.

You then extract the contents of the cab file in the my documents folder using 7zip.

Then you right click any yellow ! in device manager and say INSTALL From my computer instead of from the internet.

Category DeviceDescription Support Release Info Driver Pack Release Info

Hello  I have 2 7010s one is connected to two monitors through the displayport and the other was connected via vga I recently swapped out the vga for a DP and it will show the dell boot screen then nothing if I turn the monitor off and on it then will show my login screen. I also disconnected the DP and put the vga back in and no problems. But if both displayports are connected  the monitors will not go to power save mode.  I am only using the on board integrated graphics card with the Intel HD graphics turned on. I get the same result if it is set to auto or if it is enabled. So clearly there is something not configured right with the DPs on the 7010. 

also look in the device manager.

see if you see,  MBDA in the display driver, that is LIMP driver from MS, or not updating the driver, in windows.

if you see that, it ,means some or many graphics  features will be dead, like SLEEP and high resolutions and shaders.

LIMP means (base line lame driver but screen is snot DEAD and why it exists)

yes GEN3 iGPU are a pain some times. (split hardware there)!!!

monitors all ages, have many sleep modes even more are Deep sleep turn that off in BIOS if seen.

Monitors sleep 2 ways, mostly now,  video lines go dead, it sleeps, or if the monitors edid chip sees the sleep command from the GPU port, it goes to sleep. (that is 2 decade answer can go back to day1, me)

Old monitors 2000 to 2007 may have inside monitor sleep that you DO NOT HAVE< now. this is legacy.

your monitor  only goes to sleep (power saver ) when told to by the GPU port and no other way. !

This is why we have dummy DP , dongles on head headed PCs, so the GPU card does not go off line.

off line kills dead remote access (anydesk(tm) is mine) see that, see how it works backwards too

learn that if you turn off a monitor the GPU card (or port) can go dead, this is decided by the GPU chip driver makers not me..  (I some gpu cards here that do that, others if it sees the VGA or DVI RGB terminators missing (cable missing hint hint)the Card goes OFFLINE, too. not all cards just some, CARDS means PCI-e. x16

What iGPU does ive no idea at all , i never use it, I have vast GPU cards here, in my kits, ready to  go to work at need.

but ID DO call BAD DRIVERS HERE. seems a wise cause.

when posting do not talk about 2 PCs at the same time, very very confusing that, me blind.

But is ok to say both do it sure, but mixing symptoms on 2 PCs same post is WOW.

Onboard video only supports 1 monitor unless the INTEL VIDEO Driver is installed and working.

If there is a video card in a slot only that is supported.

Using onboard and video card is not supported.