SLI with 2 cards

Discussion in 'Graphics Cards' started by andy_rose, Jul 20, 2007.

  1. andy_rose

    andy_rose Moderator

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    OK, so with my newly purchased rig, I got 2 geforce 8600GT cards and sat up to use as SLI.
    I have enabled it on my motherboard(ASUS P5N-E SLI) and also via nvidias drivers.
    Problem is I cant see any difference in games.?
    Also there is an option in Nvidias control panel under 3D-settings named "SLI performance mode"
    It is currently set to "Single GPU" and the other options are "force split-frame rendering and force alternate frame rendering 1 and 2.
    I have no clue about SLI, but thought it would make huge differences in games.
    Any SLI gurus in here to help a poor fellow out please??

    BTW, I'm on XP Pro now, even though the same thing goes for Vista also:(
     
    Last edited: Jul 20, 2007
  2. ray_gillespie

    ray_gillespie Moderator Staff Member Political User

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    I'm no expert but have you tried setting the option in the NVIDIA Control Panel to "Multiple Display Performance Mode"? That might give you the boost you're looking for.
     
  3. andy_rose

    andy_rose Moderator

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    Yeah, tried that too with no effect:(
     
  4. Electronic Punk

    Electronic Punk Administrator Staff Member Political User Folding Team

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    Are you using games that have sli profiles?
     
  5. Aprox

    Aprox Moderator Political User

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    Also, what resolutions are you playing at? SLi is really only effective at higher resolutions and with high levels of AF/AA. You can actually see less performance with SLi over a single card in some situations.
     
  6. andy_rose

    andy_rose Moderator

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    Guess I'm a noob when it comes to this whole SLI thingie, not sure what you mean with sli profiles..but I play Colin Mcrae Dirt, Prey, Quake 4 and Company of Heroes.
    @Aprox, I guess thats it. I tried at a higher res, and the performance did not get better, but did not get worse either.
     
  7. LeeJend

    LeeJend Moderator

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    Duh, guys read the original post.

    You need to run split frame or alternate frame, single GPU ignores the second video card.

    Which rendering to use depends on the game you are playing, some work best with split, some with alternate. The choice should be automatically set by using the game profiles. These profiles are included in the nvidia drivers for older games. More recent games and some very old games may not have profiles. You will see 10-50% faster FPS (maybe higher) depending on the game.

    You can build your own profiles if necessary. Google making SLI profiles or search here on OSNN there is a post with links and more details. The game site forums should also have profile information.

    It sounds like the nvidia drivers are not recognizing the game. Not sure how to make that work automatically.
     
  8. Aprox

    Aprox Moderator Political User

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    To be honest I completely overlooked that, I was looking at other information more carefully.

    LeeJend is correct, if your currently installed drivers do not contain a profile for the game you are trying to play then most likely it will default to single GPU mode. The other modes you listed are the different ways that the driver can tackle implementing a dual GPU solution. Different games respond to the different modes. Thats why its good when there is already a profile with the proper mode selected... you dont need to worry about it. But.... since not all drivers have all games (almost though) especially newer games, you can create your own profiles in the Nvidia Control Panel. Or... you can use a handly little utility that does a better job than the Nvidia Control Panel for these types of tasks called nHancer.

    http://www.nhancer.com/

    You can use that along side the Nvidia Control Panel if you like, they do not interfear with each other. But its recommened you set the Nvidia Control Panel to "Use the advanced 3D images settings" and then close it and use nHancer, since it offers easier and more robust tools to create game profiles.

    If you have any questions about anything dont hesitate to ask.
     
  9. andy_rose

    andy_rose Moderator

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    Awesome guys, I see a big improvement in Quake 4 and Tomb Raider! Thanx :D
     
  10. Aprox

    Aprox Moderator Political User

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    Awesome! Glad we could help out. :)