an amd cpu is a very bad choice, there is no upgrade path and the single core performance is not even close to an intel i5.
More cores doesnt mean more cpu power! amd cpus are really cheap for a reason, they dont perform as well as an i5.
Don't waste your money on an amd, you will regret it
3.5 gb vram is more than enough for 1080p. the gtx 970 and r9 390 are both amazing options.