@"Pte. W. Wallis"

Listen here cunt. Your graphics card is fine for Arma. You haven't specified what i5 you have. There's a big difference between an i5 660 and an i5 6600k. Arma is a processor heavy game. I upgraded mine last week to an i7 6600k 4.6GHz and it's had more of an impact than any of my videocards. If you're upgrading your processor then it's often good to upgrade your motherboard at the same time due to the difference between an 1150 and an 1151 socket.

If you can get a decent SSD and ONLY install Arma on it, then that'll be a big difference.