So, I run an A10 7850k and decided to upgrade to a discrete GPU (R9 280x). My board is an ITX Gigabyte F2A88XN. When I disable the IGP, I get no video output from my card, but when I leave IGP on I do, despite the PCIe being set as default display port. Sure, I can just leave it enabled, such as how I have it now, but it is unusual behavior...almost concerning
have a look at the BIOS settings descriptions in your motherboard manual. You may have missed something.
On my AsRock mobo BIOS, setting the display to "PCI Express" is all I had to do. That also disables the integrated one, there is no separate setting to disable it.
Yeah, it makes sense that it auto-disables just by using a PCIE card. My default display device is set to PCIE NB on my Gigabyte F2A88X. This seems to be default with a card installed. However, I do have an option for IGP Auto, Force and Disable. I figured I would disable it just to insure that power was not going to the IGP unnecessarily, as I only have a 450 watt SFX PSU...which is the largest Gold Plus PSU I can find in SFX form.