Can't get SLI to work

stuckinasquare3

Senior member
Feb 8, 2008
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I have two 8800GT's in my EX58 UD3R motherboard. I can get both cards to work individually in both slots but only when one is plugged in. When the other card is plugged in, there's no video output. Any thoughts?
 

Rhoxed

Golden Member
Jun 23, 2007
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try the monitor on every output of both cards... sometimes it switches which port is displaying the monitor feed =]

i had one hell of a time with my 3x 3870's and filtering through 6 ports to find out it was using my 3rd cards 2nd port... figure that one out
 

stuckinasquare3

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Feb 8, 2008
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I figured it out. Not sure what the problem was though. My normal configuration is to have my card in the bottom slot (2nd slot) and I added the new card to the first slot. That didn't work. I took the card out of the second slot and just ran with the card in the first slot. Then I rebooted with the card in the second slot and it worked.

Now SLI is enabled! Errr..so I tested in counter-strike source on max everything and I got 134 fps in the stress test. With SLI I only got 156 fps. That's not a heck of a lot of improvement. Any other recommendations for tests?
 

Rhoxed

Golden Member
Jun 23, 2007
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3dmark vantage

the thing with couter strike, its so old that the vid cards have no problem playing it seperately, so when adding the second you are reaching the max your CPU can render before topping out on your video cards.
 

stuckinasquare3

Senior member
Feb 8, 2008
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Fair enough. I just loaded up BF2142 max settings. SLI disabled I got around 115 FPS, SLI enabled I got around 175 FPS. That's pretty much what you'd expect right?
 

veri745

Golden Member
Oct 11, 2007
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Fair enough. I just loaded up BF2142 max settings. SLI disabled I got around 115 FPS, SLI enabled I got around 175 FPS. That's pretty much what you'd expect right?

I hope you didn't get SLI just for those two games. I'd guess you might actually noticed the difference if you tried something that struggled or got < 60 fps with just one card.
 

stuckinasquare3

Senior member
Feb 8, 2008
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No I didn't get SLI just for those two games, they're just the easiest things to run benchmarks right now. Also I already had an 8800GT and found a good deal on a second one, so how could I not have it?
 

nenforcer

Golden Member
Aug 26, 2008
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I've got the same setup (2X9800GT) and yeah should shouldn't expect 2x theoretical performance its more like 1.75 or 1.5.

Also you may want to try the Mirror's Edge demo to test PhysX with and Lost Planet to test DirectX 10 SLI.