I'd like to upgrade my graphics card but I'm a complete noob when it comes to hardware, so would appreciate any advice:
CPU: Intel i7-3770k
Motherboard: Asus P8Z68-V
RAM: 8GB
PSU: G7 Modular 750W
GPU I want to replace: Sapphire Radeon HD 6850 1GB (about 3 years old at this point, the other parts are only 1 year old).
I'm looking for GPU options that won't requiring me changing my other parts ideally although if necessary I can change my motherboard too but it'll give me less money to play with on the GPU.
I don't have an exact budget but I'd like to get something that's currently at a good value, and will be good for AA games on a high setting (I don't need to go crazy ultra or anything), for example, Witcher 3, GTA5, Fallout 4. I have played both Witcher 3 and GTA5 with this existing setup but had to turn a lot of things to low and still got fairly poor performance which made me sad.