I'm looking at buying a used alienware m14x off Craigslist. The specs are: i7, he says gtx555 3gb, but I don't think alienware offered that gpu, I think he just means gt555, 8gb ram, 1600x900 screen for 600, good deal? Or should I buy a new lenovo y580 for 850? Or should I just build my own desktop? I appreciate any feedback.