Guide: Multiple active-monitors in SLi mode (sticky?)

Ok, we'll I've seen people ask this numerous times now, so I thought maybe it was time for a sticky. If an admin would care to sticky this thread, please do - or if not, just delete it I guess. I just thought It might help a lot of people out. Personally, I didn't do the research before going SLi, so I was very disappointed when I first enabled SLi and found that my secondary monitor turned off... By the way, this is not my original idea, but I have personally typed up this entire thread MYSELF, out of my head. Props to the guy who figured out that this works, but I felt it would be good to have an UPDATED VERSION here in the nVidia section. I've used this setup for awhile now so if you have any questions just let me know. Enjoy

Currently I have two 19" Dell DVI-input LCD's. I also have two eVGA 7800GT CO cards. My goal: to have my cards run in SLi mode, powering my primary monitor, while also having my 2nd monitor on for IRC, Ventrilo, etc.

Right now, the only known way of running a 2nd monitor WHILE in SLi mode is to use a third card (at least, this is the only method that I was able to get to work) Here's how to set it up.

Step 1: Buy a non-nVidia PCI (not PCI-e) card.
(I picked up a Radeon 7000 64mb PCI card for under $40)
Here's the eBay search link. There seem to be plenty new & used available.

Step 2: Install the card into an available PCI slot. Connect your primary monitor to the 1st port on the top SLi card. Connect your secondary monitor to the new PCI video card.

Step 3: Turn on the computer and load the drivers for the new card.
(I suggest downloading the most basic driver package available for the specific card. I found that the generic drivers included with WinXP are terrible: I was getting lag and poor video playback on the secondary monitor when using the windows-default driver. If I can find the specific driver I used for my Radeon 7000, then I will post the download link here)

Step 4: Enable SLi mode though the nVidia control panel.


Step 5: On the desktop, right-click on the desktop and hit "Properties" then click on the "Settings" tab. Click on the monitor # that corresponds to the PCI video card, and check the box that says "Extend my Windows desktop onto this monitor."


Step 6: You should now have both monitors active. The primary monitor will be in SLi mode and the secondary monitor will be powered by the new PCI video card. Reboot, then enjoy!

If you happen to use a Radeon 7000 PCI card (like I did) here are drivers you can use.
For x64:
MegaUpload - Mirror1
NorthfireIRC - Mirror2
For x86
Numerous versions can be found here


There are only two downsides to this solution:
1) The 3rd card takes up a PCI slot. If you have massive coolers on your cards (like ones that take up an additional PCI slot) then you might only have one PCI slot left. In my case, I had the Arctic Cooling NV-5 coolers on both of my cards. This meant I only had 1 PCI slot left, but I needed two: one for my SoundBlaster card and one for the Radeon 7000 card. I ended up having to remove the NV-5 coolers; putting the stock eVGA coolers back on. I don't see this as too much of a problem though, because I wanted watercool my GPU's in the near-future anyway.
2) The extra card running will use a tiny bit of your system resources (generally, just a little bit of RAM, but not enough to actually notice this).

On the bright side:
1) I now have my primary monitor in SLi mode 100% of the time.
2) I also have my secondary monitor active 100% of the time.
3) I have the option of running up to 3 active monitors in SLi mode (eh, who knows...someday maybe!)

Update:
The more expensive option to a PCI video card would be a PCI-e 1x card. Matrox just came out with one recently, but they start arouund $150 on eBay. If you've got the money and a PCI-e 1x slot, it would be a nice solution.
Here's the eBay search link for these cards.

Sticky vote from me!

.... its not all that hard... i mean SLI supports 1 monitor... its like 1 card with one port to the os..... so just get another card with another port and extend or clone... but i think this should be a sticky IMO.

so you have the sli drivers installed as well as the ati ones?

bobthemoo said:

so you have the sli drivers installed as well as the ati ones?

Click to expand...

currently, i have the full-package nVidia SLi drivers install to run the two Sli cards

for the single ATi card - i just have the very basic drivers - no extra 'dashboard' stuff or anything

i don't need to tweak the ATI card, so i didn't need all the extra stuff.

Theorie said:

currently, i have the full-package nVidia SLi drivers install to run the two Sli cards

for the single ATi card - i just have the very basic drivers - no extra 'dashboard' stuff or anything

i don't need to tweak the ATI card, so i didn't need all the extra stuff.

Click to expand...

lol my computer started FREAKING out when i went to install n e thing from ati on my machine with a 6600gt... i went to install an ATI remote Wonder and it went crazy.... ati and nvida dont mix... and why do you have to have a card from a different manufacture?

OK, I need to ask, even though it's a stupid question. Can I use dual monitors in SLI mode with a PCIe slot? My other PCI slots aren't accessible. All I have is a 3rd PCIe slot. Is there any way to make this work? Please let me know. As if that situation wasn't bad enough, I'm using Vista as an OS.

Bigdaddycool said:

OK, I need to ask, even though it's a stupid question. Can I use dual monitors in SLI mode with a PCIe slot? My other PCI slots aren't accessible. All I have is a 3rd PCIe slot. Is there any way to make this work? Please let me know. As if that situation wasn't bad enough, I'm using Vista as an OS.

Click to expand...

Yup. I would think it would work although probably not with an nVidia card

I think it is great that the OP decided to spend the time to write this up, but its pretty much common knowledge and it is not "adding a second monitor to SLI" It is adding a nother video card for second moniotr. Will be fine for a desktop and such.

I used a motherboard with dual PCIE clots and ran a 7900 in the main and x1300 for second monitor.


I imagine that nVidia will come out with dual monitor support for SLI eventually. It is not that difficult (use both heads on a single card) to implement and would be great for dual screen gamers.

I am almost 100% sure that you can't use the 3rd pci-e slot for this application. And Vista isn't a bad os at all, I got Vista Ultimate 32bit installed now and I will be updating to the 64bit soon. If you have enough memory then its a really good os. I havent had any errors at all other than what came from an unstable oc I had on my video card due to heat issues. And also, ready boost is your friend lol. to the forums also.

Also cant U run 2-way sli on two monitors each on motherboards like the skulltrail with 4x pci-e 16x

OK, now here's the deal. I managed to free up a PCI slot and have a Radeon 9000 128MB video card inserted. In Vista, I get an error message that says my PCI video card is disabled because it is incompatible with the current drivers. I think it said it's an XDDM driver and my nVidia cards are WDDM. How do I enable the XDDM card to work? Anyone have any ideas? Let me know. Thanks!