text: what does single dimm operation mean? need an answer by 5pm pst tonight. that refers to the operation mode of the memory.   there are two modes, single-channel and dual-channel.  what this means is how the computer access the memory to retreive information, if the main board only has single-channel operation, then the data of the memory only can be accessed sequentialy no matter how many memory chips you have.  when the operation is double-channel, then the memory slots on the main board has two different colors, one for channel a and one for channel b. this allows the computer to access two differents memory locations at one time, of course, if you have at least one chip on channel a and one chip en channel b.  for more information see the reference: