ATi RaDEoN :
If you can get GTX 960 4GB cheaper then go for it otherwise get something else, maybe a R9 280x. And yes 960 4gb is fully capable of maxing out GTA 5 and advanced warfare. Maybe you have to put down some anti aliasing settings but rarely.
This is complete and utter rubbish. Don't pay attention to this missinformation.
Firstly a 960 4GB version is a con, as it can't fully utilize the extra Vram over the standard model. The card is nowhere near powerful enough to do so.
On top of this it will absolutely not be bale to max out GTA 5 on any sort of palyable frame rate. To do so on 1080p you need at least a 970 GTX, on higher res you need to move to 980 and higher.
If you are ok with 60 FPS on medium to high and NO AA or filtering etc, a 280x can perform well.
However the 960 is mid range and won't give you what you are asking for.