RAM Master/Slave?

Hi, other than installing it, I know close to nothing about RAM chips. I just added one today to my iBook G4 in the upgradable slot. A computer geek told me I have to designate the updgrade (which is 512MB) as the "master" and the sodered-in module (256MB chip) as the "slave." Otherwise, my computer's performance will be adversly affected.

My question is: Is this true? Do I need to designated one a master and one a slave? And if I do, how do I go about doing it?

Thanks!