performance of having 4x256 OCZ 3700 Gold Dual Channel?

I'm thinking of getting one more set of 2x256 OCZ Gold 3700 Dual Channel to go with the one i already have? would this help memory bandwith at all, decrease it, or anything like that?

I don't think it would change your memory bandwidth, since you would still be running dual channel at the same MHz. However, I have heard that using 4 memory sticks can (sometimes) reduce your maximum stable overclock. Maybe someone who has run with 4 memory sticks can agree or disagree with this.