Optiplex 580 -- AMD hardware -- customer brochure states that dual channel operation is possible, but no one seems to know how to effect it..  the manual's sysbo diagram does not even label the dimm slots.

the two dimm slots nearest the cpu have black flaps, and the next two dimm slots (towards the top of the chassis) have white flaps.

as best as i can get from Dell, the modules are labeled, starting from the black-flapped DIMM nearest the cpu and proceeding away from the cpu:

channel A DIMM 1 [black] -- nearest to cpu

channel B DIMM 1 [black]

channel A DIMM 2 [white]

channel B DIMM 2 [white] -- furthest from cpu; nearest top of chassis

 

is this DIMM slot-labelling correct?

 

Dell also tells me that the two dual-channel kit modules should occupy channel A DIMM 1 & channel A DIMM 2  -- but this is different from what i (think i) heard elsewhere: dual-channel means that both channels -- channel A and channel B -- are in operation.

 

my questions are: which DIMM slots should be occupied for a dual-channel functioning; do i need to alter bios settings; what happens if i use two dual-channel kits -- say 2 x 2gb 1066MHz and 2 x 4gb 1066MHz -- each one being positioned for dual channel operation -- which dual-channel operation will function?