Originally Posted by ski-bum
The MSI Lighting Extreme has 3GB of VRAM so that's why I'm leaning towards a second.
I've been considering a GTX680 2GB. Do you think my framerate would be that much better over the 580?
Would I need a 4GB 680?
Ah. Good that you have the 3GB version. Normally most 580 folks have the lower one.
Well 680 will not be much of an upgrade over the 580.
30% maybe. Thats it.
In your case I might actually wait for the 780.
580 in SLI will consume more power and I believe (can't know for sure) the future 780 will give you pretty much the power of a 580 SLI, with NO SLI hassles, less power consumption and newer technology.
However no one knows when the 780 will come out.
Decisin is yours.
You won't regret 580 SLI too but I believe Kepler scaling in SLI is better than the Fermi too.
Edit : 680 4GB will make some difference in few games out there. Skyrim with mods is one of them.