Hey guys, this is my first post on this forums and my first time building my own computer. I am only fourteen, so I'm going for a less expensive build for a gaming PC. My budget is $400 (I know that I'm not going to get the top of the line with this, but it is something), and I was looking to use the Athlon X4 640. What motherboard and graphics card would go with this? I was thinking of a Radeon 4870, but I'm not exactly sure what would be a proper set up, as I'm extremely inexperienced. Thanks a lot for your help.