Question Difference between mobo DVI and VGA?

Bolychkanov

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Nov 16, 2013
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Hello.

On my motherboard Asus Z87 I have an output called DVI and an output called VGA out. I've read multiple sources say that these ports are used to access the CPU integrated graphics. However, no writer mentions the difference between these two slots. Say I wish to use my CPU graphics, using a dual link cable from the DVI slot on my monitor, do I connect it to the DVI slot on the mobo, or the VGA slot using a DVI-to-VGA adapter to get the basic low res screen? Note that my monitor only has a slot and its specifically called DVI. No additional letter.

If you're supposed to use one of the two, then what is the purpose of the other one?
 

boju

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DVI can be digital or Analogue depending on version. VGA is old and is only analogue. Digital is best where possible for better picture.

There are different DVI connections and for us to know exactly which DVI port your monitor/mobo has, give us the exact models. I'd assume your motherboard has either DVI-D (Digital only) or DVI-I (Analog and Digital).

Since you stated you have DVI, we just need to establish which type.


How am I supposed to fit a cable designed for DVI slots in a VGA slot without using an adapter? The cable has 24 pins and the VGA slot only 15

That is because Obakasama thought you have DVI at both ends, motherboard and monitor which you obviously stated. Using DVI in this scenerio would be best.

On my motherboard Asus Z87 I have an output called DVI and an output called VGA out. I've read multiple sources say that these ports are used to access the CPU integrated graphics. However, no writer mentions the difference between these two slots. Say I wish to use my CPU graphics, using a dual link cable from the DVI slot on my monitor, do I connect it to the DVI slot on the mobo, or the VGA slot using a DVI-to-VGA adapter to get the basic low res screen? Note that my monitor only has a slot and its specifically called DVI. No additional letter.

If you're supposed to use one of the two, then what is the purpose of the other one?
 

Bolychkanov

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Nov 16, 2013
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10,510
DVI can be digital or Analogue depending on version. VGA is old and is only analogue. Digital is best where possible for better picture.

There are different DVI connections and for us to know exactly which DVI port your monitor/mobo has, give us the exact models. I'd assume your motherboard has either DVI-D (Digital only) or DVI-I (Analog and Digital).

Since you stated you have DVI, we just need to establish which type.




That is because Obakasama thought you have DVI at both ends, motherboard and monitor which you obviously stated. Using DVI in this scenerio would be best.
Okay so basically use DVI if you can. And, my DVI slot doesn't actually specify type, however the dual link cable fits perfectly, so I would assume its I-type.
 

boju

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Okay so basically use DVI if you can. And, my DVI slot doesn't actually specify type, however the dual link cable fits perfectly, so I would assume its I-type.

Yeah, DVI is better.

DVI type is specified by the pin arrangement - if were to know, you do now :). DVI-I has four pins top and bottom of the horizontal line for anlogue signals. DVI-D cable can fit into this plug but not vice versa.
images



VGA was still lingering but don't really see much of it anymore on modern motherboards, it's either HDMI or Displayport. Even DVI is being slowly phased out with everything going completely digital and smaller connections.
 
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Bolychkanov

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Yeah, DVI is better.

DVI type is specified by the pin arrangement - if were to know, you do now :). DVI-I has four pins top and bottom of the horizontal line for anlogue signals. DVI-D cable can fit into this plug but not vice versa.
images



VGA was still lingering but don't really see much of it anymore on modern motherboards, it's either HDMI or Displayport. Even DVI is being slowly phased out with everything going digital and DVI is bulky.
Oh, judging by that picture, both my monitor and my motherboard are DVI-D types! Does this mean that I must connect my monitor to the VGA slot to access CPU graphics? So I would either need a DVI-D to VGA cable or a DVI-D to VGA adapter for my existing dual link cable?

You see, my GPU wasnt working so I removed it and im stuck at a black screen even after enabling iGPU multi monitor in the BIOS. I just need to make sure im connecting the monitor to the mobo properly to get the integrated graphics going
 

boju

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Oh okay, well that's a different problem. Both VGA and DVI on the motherboard route video from Igpu and either should be working.

Start from the beginning and explain what happened.

When your gpu was removed, how did you enable or force igpu without a display?

Have you cleared cmos before? Id do that first if you haven't.
 
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Bolychkanov

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Oh okay, well that's a different problem. Both VGA and DVI on the motherboard route video from Igpu and either should be working.

Start from the beginning and explain what happened.

When your gpu was removed, how did you enable or force igpu without a display?

Have you cleared cmos before? Id do that first if you haven't.
Okay I will lay ou the problem in chronological order, thanks for being already very helpful.

  1. My GPU stops working
  2. Windows thus automatocally reverts to using its own graphics. This is not the same as using my processors integrated graphics.

3. I want to enable my processor graphics for better performance, so I read in a guide that one must enable iGPU and/or multi monitor in advanced BIOS settings. When I pressed F10 to save and exit, thats when I got the black screen shortly thereafter.

4. I was not expecting a black screen, after changing the BIOS I was expecting a low res screen before installing the Intel graphics drivers.

5. I read on Intels homepage that you may have to remove your discrete video card from the mobo to even enable integrated graphics at all, so I removed the GPU and tried restarting my pc again after putting the dual link cable inside the DVI-D output on the mobo instead. But still black screen.

6. I have reset my CMOS before using the switch on the board, and I will do it if need be as a last measure to hopefully at least get the Windows graphics drivers going again. But for now I am still trying to test my CPU graphics
 

boju

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Thanks. Can you list your entire PC specs please.

Okay I will lay ou the problem in chronological order, thanks for being already very helpful.

  1. My GPU stops working
  2. Windows thus automatocally reverts to using its own graphics. This is not the same as using my processors integrated graphics.
Did you try reinstalling GPU drivers? A failing card can prevent GPU drivers from initiating and falling back on Windows generic drivers.

3. I want to enable my processor graphics for better performance, so I read in a guide that one must enable iGPU and/or multi monitor in advanced BIOS settings. When I pressed F10 to save and exit, thats when I got the black screen shortly thereafter.

Depending what GPU you had to begin with, iGPU performance most likely wouldn't have been any better.

4. I was not expecting a black screen, after changing the BIOS I was expecting a low res screen before installing the Intel graphics drivers.

5. I read on Intels homepage that you may have to remove your discrete video card from the mobo to even enable integrated graphics at all, so I removed the GPU and tried restarting my pc again after putting the dual link cable inside the DVI-D output on the mobo instead. But still black screen.

Removing the GPU should have automatically switched to iGPU, so if it didn't do this, there's something else going on.

6. I have reset my CMOS before using the switch on the board, and I will do it if need be as a last measure to hopefully at least get the Windows graphics drivers going again. But for now I am still trying to test my CPU graphics

Remove power plug from PC, locate watch size cell battery on motherboard and remove it for 5 minutes. Remember which side it goes back, + side up.

Also try reseat ram.
 
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Bolychkanov

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Thanks. Can you list your entire PC specs please.


Did you try reinstalling GPU drivers? A failing card can prevent GPU drivers from initiating and falling back on Windows generic drivers.



Depending what GPU you had to begin with, iGPU performance most likely wouldn't have been any better.



Removing the GPU should have automatically switched to iGPU, so if it didn't do this, there's something else going on.



Remove power plug from PC, locate watch size cell battery on motherboard and remove it for 5 minutes. Remember which side it goes back, + side up.

Also try reseat ram.
Okay I will try all of this!

Specs are
CPU: i7 4770k
GPU: Gtx 780 (dead, hardware malfunction, error code 43)
RAM: 16gb corsair ram
OS: Windows 7
PSU: TX 750w corsair

Note that i've given up on my GPU, so it is out of the question until I buy a new one.

I think my mistake was changing the BIOS before I had removed the GPU. With iGPU enabled, my motherboard disconnected the generic Windows drivers to look for onboard graphics, but with the GPU still intact, the onboard graphics were disabled even though they were enabled in the BIOS. So at this point I had nothing at all to drive the display.

It's probably like you say, that once you disconnect the GPU, the mobo will turn on the iGPU itself in the correct way.

Thanks for the help, I will try out all these things first!
 

boju

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Yeah try reset cmos and try 1 stick of ram in A2 slot (second dimm from cpu). Hopefully one or the two troubleshooting steps help.

When you changed bios settings to force iGPU before GPU was removed, where was the video cable connected to? Still the GPU or did you move it to the motherboard video port?

What's your monitor btw?
 
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Bolychkanov

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Yeah try reset cmos and try 1 stick of ram in A2 slot (second dimm from cpu). Hopefully one or the two troubleshooting steps help.

When you changed bios settings to force iGPU before GPU was removed, where was the video cable connected to? Still the GPU or did you move it to the motherboard video port?

What's your monitor btw?
The monitor is an Asus VG248qe. The cable was still in the gpu when enabling igpu
 

boju

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The monitor is an Asus VG248qe. The cable was still in the gpu when enabling igpu

Nice monitor, it has DP, HDMI and DVI. If you get back up and running again and buy a new graphics card, don't let DVI govern your choice and go Displayport. Your rig can handle a 1660Ti up to a 1080Ti.

Accell and Club3D are certified Vesa Displayport brands. Look toward HBR2 or HBR3 Displayport cable by these brands.
 

Bolychkanov

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Nice monitor, it has DP, HDMI and DVI. If you get back up and running again and buy a new graphics card, don't let DVI govern your choice and go Displayport. Your rig can handle a 1660Ti up to a 1080Ti.

Accell and Club3D are certified Vesa Displayport brands. Look toward HBR2 or HBR3 Displayport cable by these brands.
Yeah this whole onboard graphics thing is just for fun until I get a new GPU. Budget is about $250 though. Thanks for the tips, I will definitely look into this when buying. I will also get back to you later if I get the display running.