I have really been looking for a definitive YES or NO for the question of SLI'ing my Lenovo Dusk Y400.
I can get the add on for about $131.00 NEW and it would replace my CD Rom drive. They say it's about 1.5x the power of just the original but I haven't been able to find many comparative benchmarks. I figure the processor is fantastic and it's passmark score is in the mid 7,000 range, but the video would be the first to fall behind on the laptop. If I can SLI it and see a decent performance boost rather than buying a new one, that would be preferred.
Would it be wise to go SLI this with the ADD-ON or not bother?
I considered the same thing for my Y500. Of course, then I ended up buying a desktop and stopped caring about the laptop before coming to the decision. I don't know, because you really don't have any other options as far as upgrading it, you may as well. It'll be a noticeable increase in performance.