I'm currently looking at a New Monitor, I use my PC mostly for web surfing, Music and Sim games (Farm Simulator etc) I want to run a 4k Monitor (BenQ BL3201PT) and I'm currently running 2 AMD 7870s in crossfire. Do I need to upgrade my graphics card for sim games or will the 2 7870s be sufficient. I was looking at going with a single Nvidia GTX 980 ACX if I needed to upgrade. Is that vast upgrade to what I already have?