Nvidia Sli Question

Hi Guys I am bit confused. I need help whether I can connected my GTX 580 1.5gb and GTX 460 2gb in SLI or not. If I cant connection , how does sli works out.? Please Help me guyz
Answer #1
You were supposed to have identical cards for sli.
Recent, last year’s to now, driver updates are supposed to have enabled different card in sli, but I think it’s very flaky.
Make sure you have the very latest Nv drivers and see how it goes.
Answer #2
you have to check for a few things to make sure that SLI will work for you. -Check that your motherboard supports SLI technology
-Check to see if BOTH of your video cards are SLI compatible
-The cards DO NOT have to be identical, you CAN use different cards
-Make sure you have a working SLI connector cable/bridge
-Ensure that you have connected both cards to your motherboard and have them paired with the SLI cable
-Get the appropriate drivers and software
Both of your cards say they are SLI compatible, I don’t know what kind of mboard you have but most are compatible. All you have to do is hook it all up with the SLI cable and check the nvidia control panel to see if you have to enable any kind of SLI setting. If you see that one or neither of your cards are woking under the nvidia control panel automatically you may have to change a setting in your BIOS to enable the SLI feature.
Answer #3
-The cards DO NOT have to be identical, you CAN use different cards
WARNING:
Both cards DO have to be the same. You CAN NOT use DIFFERENT CARDS.
You can use a GTX 760 from Asus and a GTX 760 from MSI, for example. You cannot, however, use a GTX 680 and a GTX 670. THIS WILL NOT WORK
Answer #4

Can I mix and match graphics cards that have different GPUs?
No. For example, an XXXGT cannot be paired with a XXXGTX in an SLI configuration.
Can I mix and match graphics cards from different manufacturers?
Using 180 or later graphics drivers, NVIDIA graphics cards from different manufacturers can be used together in an SLI configuration. For example, a GeForce XXXGT from manufacturer ABC can be matched with a GeForce XXXGT from manufacturer XYZ.
Can I mix and match graphics cards is one of them is overclocked by the manufacturer?
Yes. A GeForce XXXX GTX that is overclocked can be mixed with a standard clocked GeForce XXXX GTX.
Can I mix and match graphics cards with different sizes of memory?
No. For example, an XXXGT 512MB cannot be paired with a XXXGT 1GB in an SLI configuration.
From Nvidia website.