Sli not working / BOIS ?

Hey first post so here goes.

My pc is pretty old now, AMD athlon X2 3800 on an ASUS A8n32-sli Deluxe with an XFX 7800GT in it. I recently picked up another card off ebay, pretty much the same but i'll come back to that. I know these cards have no problems because they both run grid and the source benchmark fine.

The problem is when i put them together and enable the drivers for SLi i get no advantages, I knew this might happen so i ran grid, CSS, aqua mark 3 (old i know, free) and 3dmark 05 and vantage with sli enabled and with just a single card in. The scores remain basically identical for everything.

Now i said the other card is different but as far as i can tell only in appearance. My origonal card is the black XFX one with the green light, the new ebay one is silver with generally a more discrete look. GPU-Z details these cards specification as identical except for their BOIS what only differs slightly with a higher version number on the ebay card.

Latest drivers all around. What can i do to get these cards working together? I've thought about flashing my Mobo and cards to newer versions but i've ran into complications with that. Any ideas anyone?
7 answers Last reply
More about working bois
  1. Originally to use SLI the video cards had to be identical – same GPU, same manufacturer and even same BIOS version. From GeForce driver release 80 on nVidia relaxed a little bit and now the video cards can be from different manufacturers, but they must be based on the same GPU. This rule is valid for all versions of SLI (SLI, Quad SLI and Three-way SLI).

    You will notice no benefit up to 50% benefit with SLI, depending on the game.
    Next time, my advice would be to get a better video card instead of SLI.
  2. they are identical cards ones just newer. How can i go about flashing a cards bios so they match?
    The version numbers are identical down to the final few digits, one is something like .08B and the other is .13 or something to that affect. I can't check for exact numbers as im on my laptop atm.

    I realise flashing one could brick it so don't worry about accountability or whatever. its my fault.

    an extra card was £10, you can't argue with that value.
  3. Download GPU-Z, save your present firmware, and go here to flash the video card.
    If you brick the card, put a PCI video card or another PCIe video card in the computer for video and reflash the card. In other words use 2 video cards to reflash a bricked one.
  4. well i've got the cards bios' matching now so there is absolutely no difference in the cards according to gpu z

    However I'm still not seeing any improvement in any programs with sli enabled. I'm going to update my motherboard bios but are there any other thing i can do to resolve this? Could the cards be bottle necked by something?

    by any program i mean aquamark, 3dmark 06, CSS stress test, grid and bf2
  5. What if the SLi bridge is broken would i get any errors or symptoms?
  6. You haven't said what resolution you're playing at? If you are running something low like 1024x768 it is likely you won't see any/much improvement. I run 8800GT sli at 1280x1024 currently (soon to move to 1080p) and the difference is only visible in a handful of the most taxing games with everything on high.
    Have you tried enabling the SLi indicator bars in the control panel to see if they move in-game?
    Re: a dodgy bridge, I had a bridge go bad and you would definitely notice!! Symptoms include the screen flashing constantly, random colour overlays - mine went green - artefacts and general highly-visible corruption!
  7. ok time for an update, in short i think its solved.

    the rez is 1280 x 1024 as that's the highest my monitor will do. now in CSS with the settings matching the example following im getting 119fps with msn xfire itunes and FF open. This is an improvement however their test rig uses a single core version of mine and my drivers have had a lot of improvements since then so I'm not sure if the difference in performance is accountable. What do you guys think?

    Test setup page, skip on to the CSS benchmark

    thanks for all of your help.
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