770 SLI 4GB and 2GB

Hi guys. I am planning on upgrading my rig with tax returns coming in and I would like to get a second graphics card. I currently have a GTX 770. Current card below.


So I have the 2Gb model and if I understand correctly if I get a 4Gb model because I want to have a 3 monitor setup it would gimp that 4Gb card because its limited by mirroring the 2Gb card. I would plan to get the same model of card just different Gb size. Is it possible to have the 4Gb VRAM to not mirror the second weaker card so its not limited by the lower VRAM or is there any other possible fixes?

Now if this is not possible is a 2Gb card able to handle multiple monitor displays at 1080 resolution, and if so what limitations do you see outside of no massive SSAA?

No it isn't possible. I'm 99% sure that SLI only uses the VRAM of the lowest card. You can't SLI a 4GB card and a 2GB card. Well, you can, but it will be limited to 2GB. Your card should do a decent job on 3 Monitors, but if you wanted an upgrade consider avoiding SLI all together. 

SLI can be a pain in the ass and most times you won't get anywhere near double the performance. Max maybe 70% at best and even that is rare. Usually it is around 20%-40% better performance. 

Don't buy the second 770. Sell your current one. Use the money to buy a 780 an R9 290 or even a 780Ti if your budget allows for it. It will be less hassle 

Get a 780Ti K|NGP|N. Sell the 770.