My question was "Are these parts compatible and do they fit in the case?" No one answered my question.
My budget is $600. Also I posted the case at the top. and 4Gb ram is enough for gaming I heard.
To answer your first two questions, yes and yes. Sorry I didn't see the case, it is not a link. You currently do not need 8 gigs of ram. That said, computers won't start using less, and it is only $20 more.