currently, i have 2 identical crucial modules in there, ddr2 pc-5300 1gb sticks. ive tried them in every combination in all 4 banks but cpu-z keeps reading them in single channel mode.
ive popped them into my dell 537mt and they went into dual channel no problem. to be fair, my 537 only has 2 slots, whereas the 531 has 4.
bios is latest, all drivers are latest from dell or manufacturer. pc is out of warranty or id call dell and ask them if this mobo even supports dual channel mode (though everything ive read online indicates it does).
im at a loss. generally im pretty damn good at doing my own tech work but this just has me stumped. the OS is vistax64 also.