Is this a good gaming pc?

[Squilliam]

http://www.dell.com/content/products/productdetails.aspx/xpsdt_420?c=us&l=en&s=dhs&cs=19&~oid=us~en~29~xpsdt_420_anav2~~

Is a better gaming PC. It costs $100 less and has a better processor and video card.

http://www.newegg.com/Product/Product.aspx?Item=N82E16883227084

Is a better $1050 machine.

http://www.newegg.com/Product/Product.aspx?Item=N82E16883229046

Is a better $900 machine.

I mean better in terms of specifications to the $$$.

I think if you have any more questions you need to tell us what kind of gaming you're gonna be doing, what size monitor you intend to use etc.