Looking to upgrade gpu

[bigpak]

I have two 980s right now, and a 144hz monitor,

 

and I was looking to get a 1080, but I am wondering if I need to get two to be able to reach 100-144 fps in games I play? Do I need two 1080s or just one?

 

 

[Canada EH]

Why do you need to reach 100-144fps?

Linus (in his video) says max is 2 if you got money to waste.

If not 1080 is sufficient.

[bigpak]

Because I hate playing at 60fps? I am trying to figure out if one 1080 is enough or if I need two. Currently I mostly play older releases such as borderlands series, skyrim, fallout series, half life series, and want to be able to play the newer games at above 60fps 1920x1080p 144hz at a decent frame rate above 60

[bigpak]

I mean I don't know if I need a second 1080 to do it, and they are pretty expensive, do you think I would get 90+ frames on the games I listed with just one 1080? 

 

Also if I buy one 1080 now, and it's a asus founders edition, could I then in the future get a pny founders edition and run it in sli?