jeffreyhjkgf1 :
So uhm I'm looking into gaming computers to buy and I want to play 4k 144 hz I was investigating and I saw that one GTX 980ti alone could handle 4k
Not really, not without turning down details. Even the 1080Ti couldn't manage all games at 60fps maxed out.
Definitely not the 980Ti.
jeffreyhjkgf1 :
so I was wondering if two could do 4k 144hz easy but then I don't know what type of procesor I would need etc etc I would like a PC with a SSD only aswell
No. SLI doesn't work like that - and generally is poorly supported.
4K monitors that can handle that refresh rate are a very recent thing. No video cards can handle that on the latest titles with max details.
The RTX 2080Ti is, I think, the first card that can do 4k max details at 60fps consistently.