3gb unpaired memory modules in dual channel 32 bit hardware


May 7, 2007

I have a core duo laptop that has two memory slots. I have two problems:

1. I want a maximum of 4GB RAM, but since the laptop hardware is limited to 32bit, that means about 1gb of that is going to be "wasted".

2. If I put in 3GB of unpaired ram (1x1gb+1x2gb), will that cause problems? Does the machine still run in dual channel mode?

I read in Wikipedia that dual channel doesn't require paired RAM to run, contrary to what I heard before (requires matched size if not speed). So what gives?

I would like to just add a 2GB module to a 1GB module to achieve the maximum allowable for my laptop, without wasting any memory. I just want to make sure that I won't lose anything here (reliability or speed).

Thanks for your help.



Most likely, the 1st GB of RAM from each SODIMM will be interlaced, running in dual channel mode, while the "extra" 1GB on the bigger module will run in single channel mode. I wouldn't expect it to significantly affect the speed of your apps to do this, but you can always install 2x2GB SODIMMs to make sure all available memory is running in dual channel mode.