Why won't these cards SLI?

I have 2 graphics cards I'm trying to SLI. I realize most of the time people do exact matching pairs but I had thought these would work together for now. PSU is 850w so that should be enough.

They are:


I don't need to be told I'm stupid, I just need help. I'm probably going to be doing some returning but this should be working anyway right? Any help is greatly appreciated.

Oh, Motherboard is:
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  1. No one is going to tell you your stupid LOL calm down. Have you loaded the newest driver and then opened the nvidia control panel and look to see if SLI is enabled? The little check box ? Oh and one other thing did you put the little bridge dohicky accross the two cards?

  2. do you have the SLI bridge on the cards?
  3. Ok, what all have you tried already?
    Are both the cards connected via a SLI bridge?
    Have you connected the PCIe Power for both the cards from the PSU?
    Which card is Primary and which card is secondary?
    What are the slots you have put the cards into on that mobo?
  4. And what drivers are you using? From the Nvidia Website or from the CD's that came with the Cards?
    Have you installed the drivers from both the CD's that came with the cards one by one? or have you installed just one driver once and which one?
  5. WHAT????????
    Where did you decipher the 560Ti and the non 560Ti from?
  6. Send the technical links to those cards where it says whatever you say.
  7. Ahh...I misread Amazon's ASUS bad...its 4 in the morning in my defense..I'm going to bed...I was wondering why the ASUS was cheaper but a better card...nope...wrong...maybe also if amazon was organized like newegg with product labels...

    The cards are both 560 so they should both work in SLI...I take back my statement
  8. Ok, taken into account. For a second I thought I must have misread it someplace...
  9. I've tried both the CD driver and the Nvidia website driver. Windows and the Nvidia control panel detects both cards, but the option to enable SLI doesn't exist. I do have the SLI bridge. I have the cards placed in the PCIe x16 and x8 slots.
  10. Also, the Zotac 2gb card is the primary, that is the one in the PCIe x16 slot and the one I have my monitors connected to.
  11. Steps I'd like you to follow:
    1. Uninstall all Nvidia Drivers. Use driversweeper to completely erase all traces of the drivers.
    2. Shutdown the system.
    3. Remove the card in the lower slot the secondary card.
    4. Reboot the system. Let the system update the drivers for the Primary GPU from the update site.
    5. Reboot. Check if drivers are perfectly installed and everything is fine.
    6. Shutdown. Insert Secondary Card in rig. Do NOT connect SLI bridge.
    7. Start rig. Let windows automatically install the second card. It will ask for a reboot. Reboot it.
    8. Check in device manager to make sure no yellow triangles , red crosses or exclamation marks exist.
    9. Shutdown. And connect SLI bridge.
    10.Start up and check Nvcpl for setting.
    11. Enable SLI through the Nvcpl.( Nvidia Control Panel)

    Post if you follow the exact steps in the order and what result do you get.
  12. In progress. I zapped everything Nvidia with driversweeper. Windows would not automatically install the driver for the first GPU, so with that, do I install from the CD or directly from Nvidia's website?
  13. directly from their website.
  14. Alright, I followed those steps. Both cards are running 285.62 driver and both are detected without any marks in the device manager. The 2nd GPU is being used for PhysX.

    However, still no option to enable SLI.
  15. Best answer
    The problem you are having is because both cards have different memory sizes. There is a work around offered by Nvidia's website. You must use a program called CoolBits:

    Can I mix and match graphics cards with different sizes of memory?

    When purchasing a second graphics card, you should try to match the memory size so that you are ensured full value and performance from your purchase. However, while it is not recommended, NVIDIA does offer the flexibility to run graphics cards with different sized memory by using CoolBits. Using CoolBits (value set to 18), you can force both of the cards to use the lower of the two memory sizes and operate them together in SLI mode. When dissimilar memory sizes are enabled to work together using CoolBits, the effective memory size for each card becomes the smaller of the memory sizes.
  16. Thanks bystander, this worked. I realize it's not ideal to have a 2gb card running as a 1gb. I'll have to decide what to do, as it was a free upgrade that came with the system. I'll probably return the ASUS and get another Zotac 2gb.
  17. Best answer selected by Walrusbear.
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