I'm probably picking up some DDR3 within the next couple weeks and could use some advice from those who are currently using it.

Since the best DDR3 IC's out atm are D9GTR/D9GTS and are of 128mb density per IC, 1gb modules made with them are single sided, and 2gb modules are also available double-sided.

My question is, which would setup would yield better results? Four single-sided 1gb modules, or two double sided 2gb modules.