i was wondering what exactly does duel channel ram mean? I have an AMD HP Media Center PC AMD X2 Duel Core 2.20ghz 2 gig 1gigX1gig ram DDR3200 /4 dim slots up to 4ghz Mobo Amythyst MS7184 is Dual channel compatible also wondering if I add and extra 512 in the 3d slot and leave the 4th empty does that disable duel channel? does it have to be 2 and 2 in order to work? and what would be the difference if i added the 512 and it did disable duel channel? is having it duel channel make it any better then just adding the extra 512 to the memery. and do they both have to be 512 or can i put 512 and a 256 in the other 2 to make duel channel work?