Is it worth the new gpu?

Solution
According to a comparison between the individual cards (non SLI), the Rx480 more than doubles many aspects of that card. Knowing this, and that SLI doesn't actually even double the specs of the card, it would be a pretty good step up. As far as price? I'm not sure. I'd suggest looking up comparable used 950 cards.
As far as between those two? I can't honestly say. I know Nvidia, not radeon, sorry.

Comparison
According to a comparison between the individual cards (non SLI), the Rx480 more than doubles many aspects of that card. Knowing this, and that SLI doesn't actually even double the specs of the card, it would be a pretty good step up. As far as price? I'm not sure. I'd suggest looking up comparable used 950 cards.
As far as between those two? I can't honestly say. I know Nvidia, not radeon, sorry.

Comparison
 
Solution