Upgrading PC - El Questiones

[Kinetik*]

I started playing Arma 3 and it's really very resource intensive. It renders lots and lots of objects so I'm not getting a very high frame rate. I'm currently running a Dell Inspiron 3000 with an nVidia GeForce GTX 750 ti. Everything else is stock.

Where should I start to increase FPS? Should I upgrade the GPU? More RAM? Cooling?

Heeelppp meehhhh