The problem is memory to run those high resolution Screen. Yours GTX 660SLI only have 2 GB so running it on 4k wouldnt be optimum at all. GTX 970 sli doesnt do 4k justice either, I a currently running 2xR9 290x and 4k tv but barely play any game at ultra high settings at all. So I am returning...
I would get Samsung Tab 4 due to you already have another Samsung. So it would make use of all your android program and other samsung features. Eventhough FireHD is great tablet but it is bulky compare to Samsung Devices.