Nitemare3219
I don't know how you're only using 3.5 GB Noodle... I am still using 3 GB in some games at 1440p. When I was gaming at 4K, it would stick at 3 GB because that's all I have to give! And games that needed more (depending on settings) would choke badly. I have the horsepower to game at 4K easily, but the VRAM makes it impossible. BF4 at 2x MSAA choked. Evolve chokes at 1440p. Watch_Dogs chokes. I almost guarantee GTA V will choke 4 GB. It is not enough for 4K gaming for a year or two from now.
The VRAM boogie man does exist. And I never hoped I'd see him, but I did. And now I have to upgrade my year old $700 cards because NVIDIA got greedy and knew it would turn out that way.
If you have the need to be on the bleeding edge of resolution and monitor tech, then you should be prepared to be on the bleeding edge of GPU tech, always. That means that expecting a card to last longer than the current generation is unrealistic.
This is also a little bit of a unique time given that a resolution shift only comes once every decade or so. I'm not sure anybody ever expected 780 Tis to be able to game at 4K for long periods into the future considering 4K monitors barely existed when the cards were released. It wouldn't have been adequate for me, performance wise, even when it was brand new. I know this because I ran 780 Ti SLI for a long time with 3x 1080P (3K) surround, and I had to turn settings down in BF4 by quite a bit to achieve desired performance (100+ FPS at all times). Any sort of AA was totally out of the question.