single or dual DDR2 SODIMM modules for best performance?

[hexwrench]

I asked a sales rep at ProStar why I couldn't configure my Clevo M570RU/Sager 5790 (Santa Rosa Intel 965 chipset) notebook with 1x2GB DDR2 modules instead of 2x1GB modules and he said that it was because it is dual-channel. I am pretty sure he is wrong and I can put just one memory module in the system, but do I need 2 identical modules to utilize the dual-channel feature and get the best performance? In other words, is 2x1GB better than 1x2GB?

[kenc51]

Yes, you can 1x 2GB.
2x 1GB is better performing (dual channel) but 1x 2GB allows you to upgrade to 4GB later on by just adding one more stick. If it was me, I'd go with 2x 1GB since it's a laptop.

[hexwrench]

Was hoping for a quick answer, but instead I educated myself on memory architectures. In the newer Centrino platform architectures (ones that support dual-channel RAM such as Napa and Santa Rosa) there are only 2 memory slots. These are separate channels. If I have only 1 slot occupied then I am operating in single-channel mode and at half the transfer rate than if I had both channels occupied. Duh.

[hexwrench]

Yes, you can 1x 2GB.
2x 1GB is better performing (dual channel) but 1x 2GB allows you to upgrade to 4GB later on by just adding one more stick. If it was me, I'd go with 2x 1GB since it's a laptop.

Thanks kenc. I agree with 2x1GB. If I was getting Vista then I'd just go ahead and get 2x2GB but I'm not quite ready for that.

[Apoptosis]

the cheapest route is also the best performing route and that is two 1GB modules... With a 32-bit OS 4GB is a waste and those 2GB SODIMMS are still pricey.

Nate