In the past, RAM modules had to be installed in a certain order or in certain mod sizes so that all slots were filled... at least that was my understanding. With the current motherboards, is this still a problem, or if I have a board with 3 slots am I able to now just plug in one 512mb mod into any slot I like and leave the others empty?
Well, for the most part, it doesn't matter what size or position you place them, although, some motherboards do prefer the sticks to be in a specific slot. But yeah, you can leave the other slots empty if you want. The only exception to this is Rdram, where you HAVE to install memory in pairs, and any empty slots HAVE to be filled with c-rimms.
Soon enough, Intel will make the i845s...imagine dual channel Sdram...*shudder*