Dual channel

[[Psych]]

Depends on the board/chipset moreso than the type of CPU (intel/amd) it supports i've found. It's usually 1+2, 3+4, or 1+3, 2+4 as previously stated (or 1+2+3+4 of course). Not sure why you want to know which will have 'priority' as I don't understand what you mean. For dual-channel to work properly you need to make sure matched pairs are fitted (speed and size ideally). Although dual-channel will most likely still work on your board, I would see about getting rid of those 512 sticks and maybe placing some more 1GB sticks in (check your chipset doesn't have a celing of 2GB though).