I have a Dell Dimension 8300 that is still trucking along. A while ago I had ugpraded to 2x1GB in it. Over the weekend, one of the modules died, so I went and bought another 2x1GB (to run in matched pairs). I have noticed from time to time that memory heavy applications (GIMP, etC) do get a little bogged down with only 2GB of RAM. My question is, am I better off pulling the 'odd' module, so the system will only have a matched pair, or leaving the odd module in, and having 3GB (instead of 2GB) of RAM?
The loss of dual channel does have a significant impact on memory performance, but that only has a small impact on overall performance because performance is rarely determined by memory throughput. One would expect that the significant change in memory size would prevail because more memory means less disk I/O, and disk I/O often affects real world performance. I'd leave the odd module in.