Alienware Voltaire Desktop vs GatewayDesktop

Hey people of tom's hardware,
I've decided to buy a new pc for myself. I'm into pc gaming a little but i would also like to use it for typing up some worksheets and such... but i was wondering the difference between:

AlienwareVoltaire Desktop / Intel® Core™ i5 Processor / 6GB Memory / 1TB Hard Drive

GatewayDesktop / Intel® Core™ i7 Processor / 8GB

The alien ware was about $500 more but it seemed like the gateway seem to have better specs. I'm wondering if i totally missed the ball on this one or something...

i also have a Radeon HD 5770 1gb Gddr5 graphics card and a 650 earthwatts antec PSU that i could put in from my old pc.

Here's the link: http://www.bestbuy.com/site/olspage.jsp?id=cat13504&typ...*1218255560078&unPro

Hopefully my info is all accurate and thank you for the help.