sli slots?

I am not sure I understand it. Supposing I have 2 pci-e slots and two 7900 GS cards then I can set up a SLI effect. Is it correct?

 

SLI is pretty amazing re: performance but be forewarned, at this point in time, one can not run SLI with dual monitors. Using the above example, you will have 4 DVI connectors and can most certainly run dual monitors, but they will be run in a normal mode, not SLI. The only reason I post this is because it was new news to me about three weeks ago. Am now going to try a Matrox DualHead2Go off of a single video output to see if SLI will run a dual monitor setup this way. I'll know whenever I get back to the home 20.

 

You'll need a mainboard that supports SLI.

A friend of mine recently got an Nvidia 7950GX2 and can either run it in SLI mode or dual-monitor mode.

 

Yes, understood. I probably wasn't clear enough. One can run either/or but your friend will discover he/she can't run dual monitors in SLI mode. Running dual monitors can't be done at this time while in SLI mode. Have your friend check his/her performance and frame rates - better yet, don't - they will be disappointed.

 

Actually, half a 7950GX2 is nothing to sneeze at.

Believe or not he can't switch back and forth due to a bug in the latest Nvidia drivers - it blue-screens when he tries to go from SLI mode to DM mode. So for now, he just stays in DM mode and says the heck with SLI.

 

I guess thats my beef with SLI - one would think dual monitors should be a piece of cake. Although I think I have a solution that is going to work, this is kind of the like making the fine print so small that it can't be read.

As to another problem with NVidia drivers, its also my understanding that NVidia and Vista won't play nice together - lets just say its enough of a problem that Nvidia has just set up a website dedicated exclusively to resolving problems associated with this and I expect we'll be hearing a lot more.

 

Hi Greeneye,
Without going back over my reading...be careful that you are talking about the graphics slots and not the PCI-Express slots. The graphics slots are PCI-Ex16 and are different to the add-in card adapter slots which are PCI-Ex1. (Ex16 graphics slots are quite long, Ex1 add-in slots are quite short). You need two PCI-Ex16 slots to run SLI.

Edit: "You need two PCI-Ex16 slots to run SLI ", see Gary's quote

Motherboards can support nVidia's SLI or ATI's equivalent Crossfire. You cannot run (twin) nVidia cards on a Crossfire system and visa versa.
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Hi Rockster, the dual monitor situation, I would just suggest that you be sure to try and set up the monitors using the nVidia "control panel ", not through Windows Display settings. I added a dual monitor (not SLI though) recently and by using Windows display properties, it turned the screens into a dog's breakfast. After resetting, I went to the nVidia controls and found out to how to work with those (actually, I thought I might have trouble using the large screen for television and the normal screen for games, disabling one or other, but it has worked out fine). I have only recently tried setting this up so I may be a long way behind you, especially if it relates to SLI. I found the inability to use Windows display properties interesting though and by that experience, it must cause some "What the heck is happening here?" for others.

So...from what I can see, if you have the nVidia control panel installed and you want to set up dual monitors, don't do it through Windows Display, only through the nVidia controls (whether or not it is similar for SLI???)

Matt

 

Dual monitors or dual displays is not and should not be a problem. Using dual displays or dual monitors while running SLI is the problem - it can not be done without additional hardware. Thanks for your input, Matt, I'm well aware of the suggestions you made but perhaps others aren't.

 

OK, a little update for any curious inquiring minds.

It is and has been understood that one could run a dual monitor setup with two video cards that are SLI capable with the drawback being that this can't be run in SLI mode. SLI mode and the corresponding fast frame rates that can be achieved with it are currently restricted to using one output only - thus one monitor.

Enter the Matrox DualHead2Go device which distributes (for example) one input (1024x768) to two monitors encompassing a total screen area of (2048x768) or (1024x768) each. Technically, the computer is running in SLI mode but the frame rates are so bad compared to SLI on one monitor, its not even a good substitute for running dual monitors in a non SLI configuration.

Don't get me wrong, the DualHead2Go is a nice piece of hardware for its intended use despite its being somewhat pricey. However, its no answer to taking advantage of an SLI configuration while trying to run dual monitors.