Aubrain

Good choice. Too bad nintendium has traces of radiation in it.

So I managed to get a much better quality build for a few less dollars.

Rockstar did a terrible job of optimizing GTA IV (since it's a console port) so don't expect it to run well on good systems. Best advice is just to turn down anisotropic filtering because it makes the game quite slow (at least for me anyway) and turn down the other options if needed. Also, read this as well and see if the first suggestion works.

I'm not that tech savvy, so I'm not sure if I've chosen good parts or not. Any suggestions for improvement would be good. Keep in mind I'm willing to spend up to around $650 on it though.

Is putting a computer together really like lego?