How does a MB decide if memory will run single or dual channel?

[SeanM]

I have an ASUS P4P800SE MB. I cannot seem to get memory to function in dual channel mode. My first pair of DDR module was a matched pair of Corsair Value Select. This memory caused stability problems in my system and would not run in dual channel. I am now running a stable configuration with 2 X 512 Crucial CL 3 memory. Only problem is the MB still does not run in dual channel mode.

My questions are:

How does A mother board decide if 2 memory modules an run in dual channel mode? Is it the SPD?

Does anyone have any tips for getting memory to function as a matched pair in dual channel mode.

Thanks for your help,

-Sean

 

[SeanM]

no takers on this question?

 

[bacillus]

You need to install each ram module in the designated slots in order to run in dual channel mode.

 

[Peter]

You need to have a functionally identical pair of DIMMs in corresponding slots on channel 1 and 2.

 

[SeanM]

Assuminig that I do place the memory in the correct slots (1 and 3 for the P4P800SE) and the memory is the identical make, how does the MB actually determine if the memory can work in dual channel. I was wondring if if performs some tests and the memory, or does it jst read the SPD for each module and see if they are identical?

-Sean

 

[Peter]

It reads the SPD from both DIMMs, compares and then just does it. There's nothing special to dual channel mode, that's just running identical DIMM pairs in parallel.