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User has an Optiplex 755, it has onboard VGA. User wants dual monitor support. I have a small profile DVI extender and a large profile PCIe video card. The DVI extender does not fit in the riser card because of the form factor. When I install the PCIe video card the Dell BIOS (A17) want to use either the onboard VGA **or **the PCIe, not both and will disable the one i'm not using. I cannot get Windows XP to enable the card disabled in the BIOS.

The motherboard has a riser that yields 1 x PCIe and 1 x PCI both large profile. the motherboard has 1 x PCI small profile.

How can I force the BIOS to leave both cards enabled? Do i have any other options besides buying a dual DVI out video card?

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4 Answers 4

up vote 5 down vote accepted

There is no way on most motherboards to enable onboard graphics and an add-on GPU at the same time. A GPU with two outputs would be your best option.

Another (possibly less expensive) option is to buy a USB to VGA/DVI adapter. Here is one I hear good things about, not the cheapest one out there, but you get what you pay for and EVGA is a good brand.

If your motherboard had two PCI-E slots you could also run two single output cards at the same time, but the machine you listed only has one PCI-E slot, so no go there.

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3  
+1 -- this is because often the onboard video and the PCI Express slot share the same PCI Express lanes. –  Billy ONeal Nov 15 '10 at 19:38
    
@Billy good to know, thanks for sharing. –  ubiquibacon Nov 15 '10 at 20:31
    
+1 for USB adapter. If you don't need any rendering power (or to go any higher resolution than 1920x1200) this is the best solution –  Shinrai Nov 15 '10 at 22:13

You will need to buy a dual dvi out card. I just want to add that I have upgraded quite a few optiplex 755's with dual dvi video cards. The problem you may run into is that the power supply is very underrated and does not provide enough power for most newer cards. I ended up using nvidia 8400 gts's, not very powerful but will be fine for just dual output.

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Were the Optiplex 755's you worked with slim towers? Checking some numbers, I believe that those have lower ratings for the power supplies in addition to some of the form factor issues in the OP. –  AlanSE Nov 2 at 21:10

Yes, you can have dual monitors using the on board GPU.

You need to purchase a card which sits in the PCI-E slot and extends the onboard GPU to give a 2nd output.

I run 2 monitors on a Dell Optiples 755 using this:

http://www.google.co.uk/url?sa=t&source=web&cd=11&ved=0CBYQFjAAOAo&url=http%3A%2F%2Fh18000.www1.hp.com%2Fproducts%2Fquickspecs%2Farchives_North_America%2F12008_na_v5%2F12008_na.PDF&rct=j&q=sil%201364a&ei=jUgUTtSKIseZhQeGq-jZDQ&usg=AFQjCNFexb9fca-YAkuCDeA1QbU3IUOKrw&cad=rja

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You cannot use 2 video cards at the same time. (at least not on consumer level computers, gaming computers can sometimes use 2 cards linked together, called SLI Mode).

However, you can find DVI to dual VGA adapters, and that might be what you need.

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You can use two video cards at the same time, you just cannot use onboard graphics in conjunction with an add-on GPU. I have used multiple (3 at the time of this writing) GPU's in the same rig without using Cross-fire or SLI. You can even mix ATI and Nvidia in some situations. The link you provided is a splitter, but it will only mirror the primary display, and I doubt this is what the OP wants. –  ubiquibacon Nov 15 '10 at 19:23

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