Re: if there is a Rule as to which order they go in?   there is no rule.  either way works and there is no difference in performance. Re: when you have Only Two RAM Slots, those are Two Different Channels right? if the ram are identical in spec, they run dual channel; if different spec, single channel. Single-channel (asymmetric) modeThis mode provides single-channel bandwidth operations and is used when only one DIMM is installed or when the memory capacities of more than one DIMM are unequal. When using different speed DIMMs between channels, the slowest memory timing is also used.
Hey guys, Optiplex 3020 Mini Tower with Two Ram Slots.  I have 2GB and 4GB ram chips and I'm sure the smaller chip was in Slot #1 when I took them out.  Now that I'm putting them back in thought I would ask if there is a Rule as to which order they go in?   I don't think it matters, but may have read somewhere that you put the largest ram chip in Slot 1 on a system with only Two RAM Slots, is that correct or doesn't it matter?  I think it will run either way, but is there a difference in performance? Another thing I always wondered, when you have Only Two RAM Slots, those are Two Different Channels right?
Which RAM size goes in Slot #1?