I would like to get another 1 g of ram. Right now I have this pc : http://h10025.www1.hp.com/ewfrf/wc/genericDocument?lc=en&cc=us&docname=c00280666 w/ 1 gig of DDR SDRAM 184 pin PC3200 2x512 ram. MY question is, can I get another one gig in just one stick, instead of 2x512? That way down the road I can get another 1 gig stick (I have four total slots) ? Or do they run best if you have 2x512 w/ another 2x512? Thanks for any help fellas!