Will your system run faster if you install two 256 mb dimms or one 512 mb dimms on a dual channeling motherboard?

In order to take advantage of the Dual Channel option on your motherboard, you will need a matched pair of memory.

If you only install one stick of 512 MB memory, you will have to turn off the Dual Channel capabilities on your motherboard.

If you install a matched pair of 256 MB memory, you can keep Dual Channel enabled.

I would recommend buying at least 2x512 MB if not 2x1 GB of memory. Prices for 2x256 MB may be very expensive compared to 2x1 GB.