with the nvidia gt640 i doubt it will "max" really any games other then like minecraft and the sims at 1920x1080 lol
idk much about the game dayz, but the nvidia gt640 is a relatively low end graphics card.
alienware are overpriced, you pay for shiny lights and the brand name. (alienware = dell, and dell like any other computer manufacturer, uses the cheapest possible hardware for max profit. so dont think they are "higher quality" or anything....)
http://www.newegg.com/Product/Product.aspx?Item=N82E16883227435
http://www.newegg.com/Product/Product.aspx?Item=N82E16883227408
both of those computer demolish that alienware....
EDIT: DO NOT LISTEN TO JAMES.... his answer has been reported for spam... he is just spamming HIS OWN ebay computers...
first off you shouldnt buy from ebay for things like computers lol
but those computer ARE NOT gaming computer
-1st one is a slim case, and has NO graphics card, and being slim limits graphics cards to be able to be put in.
-2nd one has a FIRST GENERATION i7 (they suck btw), and an old 5750 (which is an ok mid range card). Its barely better then the alienware... and used....
-3rd one again NO GRAPHICS CARD.
ALL THREE ARE DRASTICALLY OVERPRICED!
he is trying to scam by falsely advertising them as "gaming" computers...
both the newegg computers i linked are FAR FAR better an cheaper then the 2nd one....