Which PC is better for gaming and overall performance?

http://www.thesource.ca/estore/product.aspx?language=en-CA&product=8009200&category=Desktops_English&catalog=Online&tab=2#more

http://ca.gateway.com/gw/en/CA/content/model/DT.GEJAA.001 Computer store selling it for $489

Don't suggest any other model or to build my own please.

Which one will run GTA IV, Minecraft, and Dayz better? Which is less likely to lag on the internet and which one is better bang for your buck.

Added (1). I also should ask if the first one from the source has a dedicated GPU or not? I know the second doesn't

Either hp or dell or apple

The Gateway is a little better than the DX, but they're both weak computers.

Get this one - http://www.palicomp.co.uk/gaming-pcs/amd-quad-bulldozer-gamer.html

(There's a list where you can change the specs if you like, but if you just click the Buy Now button you'll see the specs they offer for $499, believe me it sh*ts all over the other 2 computers you linked.