Display has blank screen when connected to onboard graphics port Intel Skylake i7 + HD Graphics

[ta1001]

I have the following PC configuration:

Intel Core i7-6700 3.40 GHz 6th Gen Skylake Processor
ASUS Z-170 Deluxe Motherboard LGA 1151 Socket, 100 Series Chip set
ASUS STRIX NVIDIA GeForce GTX 970 Graphics Card
Corsair Vengeance LPX 16GB DDR4 RAM 3000MHz C15
Cooler Master V650 (650 W) Power Supply
WD Black 1TB Internal Hard Disk 7200 RPM
Seagate Barracuda 160GB Internal Hard Disk 7200 RPM
LG DVD+-RW 24x

This is using the Intel HD Graphics connected as HDMI as onboard graphics.
Since I am getting a blank screen/black screen what did I do wrong or what is the complete procedure to get it to work?

 

[Multipack]

If your graphics card is attached it will disable Intel graphics. Plug the video output into your card.

 

[SkyNetRising]

There is BIOS setting that enables output from iGPU, when discrete graphics card is connected.
It's called iGPU multi-monitor, set it to enabled.
It can be found under Advanced/System Agent Configuration/Graphics Configuration.

 

[ta1001]

I already did that, saved settings and exit. Still getting the same problem.

 

[SkyNetRising]

Then what's left - you have to configure Display Driver settings and enable secondary monitor.

 

[ta1001]

Is there a way to make both displays show the desktop or use both separately for different purposes like

use integrated display for file/web browsing, movies, music and other non-graphic intensive work
use discrete display for games ...
?

 

[Joseph_133]

make sure you're using a Dual Link DVI cable because a regular DVI cable is not compatible with the higher frequency and bandwidth of high end graphics setups.

i just found this out after going through everything down to RMA'ing the MB for a new one. turns out the cost was a $10 fix for a 10ft Dual Link DVI cable