Let's read what it takes today.
Notice that at 1080p even that single 980m didn't hit 60FPS. Wow, for you to hit your goal I bet you are into those Titan cards and forgetting 4K for now.
A single Titan X card is 988USD today So that leaves you 22 bucks for the rest of the PC.
ok I'm starting to think about building a pc, one powerful enough to play any game on full HD without struggling! so should i go AMD or Intel, what graphics card, how much memory? should i go water cooled? also if you can suggest exact part that would be awesome!!! just trying to gauge how much it will cost! realistically id like it to stay under $1500 AUD (around $1000 us, not including monitor and keyboard etc.)