PCIe graphics works ONLY when integrated graphics enabled

[BrianWild7]

I recently installed a PCIe graphics card (nVidia GTX 750 Ti) on my ASUS P8Z77-V MB running Windows 8.1 and an Intel i5 processor. (The goal was to get displayport so I could use a higher resolution monitor.)

In the BIOS, I changed the "system agent" graphics setting to make the PCIe graphics card the primary video.

When I do that the machine seems to boot, and the MB splash screen (offering the option to enter BIOS) comes up on a monitor attached to the PCIe videocard, but Windows 8.1 never fires up the PCIe videocard.

If I set the MB to enable integrated graphics, the machine boots into Windows fine and Windows uses the videocard. Monitors attached to the videocard get the Windows display, and if no monitors are attached to the Intel integrated graphics, the Intel graphics software does not run.

The problem is that with the Intel integrated video set to be the primary video, I don't get the splash screen on monitors attached to the PCIe card, nor, I suspect, would I see Windows recovery screens, should something go wrong, though I don't know. If I attach a monitor to the Intel integrated video, then Intel's graphic engine runs in Windows, and I'd rather it did not.

As per usual, I don't know if this is a Windows problem or a MB problem or a graphics card problem. Since the MB bios splash screen goes to the right monitor for the MB setting, I am presuming the problem is in Windows. But, I cannot imagine what that would be.

I did the usual updates on general principles: so latest MB bios, latest Intel and nVidia drivers, all Windows updates.

Any help thinking this thru would be appreciated.

 

[popeye]

Not sure how your motherboard works but may need the Intel graphics enabled for the dedicated card to work. Do you have the latest Intel graphics drivers installed? Have you tried installing the Nvidia drivers when on the Intel graphics?

Could also try reverting to the basic graphics drivers in Device Manager when on the Intel, then switch to the dedicated in BIOS and see if it will boot with the basic driver installed.