Unfortunately you're at that point that if you want to hit 4k, you're going to need to upgrade both your GPU and CPU. You can always but the 1080ti now and use it with the 8350 until the 8700k comes out. Just keep in mind that the 8350 is going to severely hold it back and I don't think you'd have a good 4k experience. Remember to hit up Micro Center when you decide to get your cpu/mobo. They offer insane deals on cpu/mobo combos. Watch Slick Deals or Reddit's Build a PC Sales if you plan on buying ram now. Personally I'd wait until you purchase your cpu. Do you currently have a SSD?