I currently have a gtx 780 but I feel with most newer games its not going to handle 1440p very well and I want to upgrade it. Should I get a used 780 for sli, about $300, or get a 1080, about $800? I don't know the performance boosts for a 1080, but I know that at 1440p,for most games at least, I will get me about at least 80% more frames with another 780. I'm also open to getting a 1070 if that works, but that'll be about $500-600.
If these numbers look off its cause I live in Singapore.