gigabyte amd r9 270x
easy overclock
off course every card is different, but this should give you an idea, your gpu maybe will get better results, maybe not, come on people think a little, overclock is no exact thing, every pc component behaves different even among the same gpu chip they all are different
this is just a stupid example on how to change values, and maybe some of them will work for you
if you get 1200 gpu / 1600 ram, you are lucky
but at least you should get 1100/1500 minimum average, 1150/1550 better than average, 1175/1550 better yet
crysis 1, gta 4, are great games to test, you can pass 3dmark ok, but play a little crysis and then crash, always it is better to play some hard games to test
fan speed is up to you too, i prefer to manually put 70%
core voltage, do not worry, it is 100% safe, it makes your overclock more stable