I would try to hit for 2 GB of ram. I know because I play it on 2gb of ram and it takes up a decent amount . so I know 1 wouldn't be enough. 2 I would say is minimum and 4 to be on the better side
i decided to run asphalt 8 and on my 8 GB machine is uses around 79 MB. but on my graphics card it shoots up to like 500 Mb. so that means if you have a 512mb graphics card you are good