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Is it normal that when you connect a GPU to a motherboard, the video output from the motherboard connectors disappear, and only the GPU connectors give the video output?

This is relevant to me because my motherboard has a good old VGA connector whereas my GPU only has DVI/HDMI and modern stuff, and the cheap, cheap screen I bought only has a VGA connector. And GPU doesn't even ship with DVI-to-VGA adapter...

SPECS (although this might not be so relevant):
Motherboard: Gigabyte Z77-D3H
GPU: Sapphire Radeon HD 7950
Screen: SAMSUNG SyncMaster S22B150NS (which is quite -let's say- basic...)

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This depends on the motherboard, but a Z77 board should support this. There's probably a BIOS setting to adjust the behavior (being unfamiliar with these boards I couldn't tell you what exactly it is, hence just leaving this as a comment). –  Shinrai Dec 19 '12 at 0:06
    
This is often a BIOS/UEFI setting/option for whether onboard video is active or disabled when you've got a video card in the system. –  ernie Dec 19 '12 at 0:19

1 Answer 1

up vote 3 down vote accepted

Looking at the manual for your motherboard, p.50 of the PDF mentions settings of note:

Init Display First

Specifes the frst initiation of the monitor display from the installed PCI graphics card, PCI Express graphics card, or the onboard graphics.

  • Auto Lets BIOS automatically configure this setting. (Default)
  • IGFX Sets the onboard graphics as the first display.
  • PEG Sets the PCI Express graphics card on the PCIEX16 slot as the first display.
  • PCI Sets the graphics card on the PCI slot as the first display.

Internal Graphics

Enables or disables the onboard graphics function. (Default: Auto)

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Thank you for you reply. The 'Init Display First' option is just what screen you get at startup, no? And so you mean I should put 'Internal Graphics' to enabled instead of auto? So this will then redirect the video signal from my GPU to the motherboard VGA connector? Can I be sure it won't be using the processor's graphic solution then? –  reverse_engineer Dec 20 '12 at 8:57
    
The first option sounds like which video comes up first during the boot process (and what Windows would recognize as the lowest displays), while setting the second to enabled should ensure that the onboard video is active, even when there's a dedicated video card. I'm guessing it disables it by default when there's a dedicated video, so no system memory is used for video . . . –  ernie Dec 20 '12 at 16:48
    
Ok thanks, indeed by setting the second option to enabled I have a video signal coming from the board's VGA. But then do you know if I play metro or something now, the GPU will do the graphics even thought the onboard graphics are enabled right? Or will the onboard graphics use the Intel HD Graphics? Basically I'm not sure whether "onboard graphics" means the board just takes the video signal from the GPU and outputs it through the VGA, or if he uses the Intel Graphics so games like Metro won't run smoothly... –  reverse_engineer Dec 20 '12 at 17:55
    
@reverse_engineer it'll use the Intel HD graphics, as that's the video card you're display is connected to (the one exception to this that I know of would be Optimus enabled laptops, which will use a second video card, but write to the frame buffer of the onboard video card) –  ernie Dec 20 '12 at 21:37
    
Ok, thanks man! –  reverse_engineer Dec 21 '12 at 0:13

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