Can I SLI two different graphics cards?

No, you cannot.

SLI only works for two graphics cards which are IDENTICAL models, i.e. a pair of GTX 660 cards, a pair of GTX 560 Ti cards, a pair of GTX 470 card etc.

Crossfire (for AMD cards) is a bit more flexible. It works for a pair of cards from the same family/series (the first two digits of the card model must match) So for Crossfire you can combine a 5750 and 5770, or 7850 and 7870 etc. But for SLI (Nvidia cards only) they must the the same card model, based upon the same GPU.

you may no longer SLI a GTX 560ti and a GTX 550ti. The taking part in cards might desire to the comparable variety. you will possibly choose yet another GTX 560ti to run SLI (presented your board helps it). you may besides the undeniable fact that use a distinctive variety of GTX 560ti. you may SLI an EVGA GTX 560 ti and a Gigabyte GTX 560ti.

This is not possible. SLI requires you to have the same graphics card.

No you F'n retard

There isn't a place on the net that doesn't explain how SLI works

Absolutely not. The GPU has to be the same class:

7xx

5xx

4xx

RAM can be different. It will just use the amount of RAM on the lowest card.

I have a 590 and 580 SLI'd right now. please know what you people are talking about!

Some people on here are such dumb asses, I don't answer many questions.

This is from the link below:

Can I mix and match graphics cards if 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?

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.

Not possible they must both be the same cards .