After an earlier recommendation from DrGuitar (Thanks) that I may not be able to gain the full use of 4 GB of RAM in my DAW, I did some additional research. As I was warned, Windows XP (32-bit O/S) is limited to a little over 3GB. This is due to part of the available memory addresses beyond 3GB being allocated to other PCI devices. So, investing in 4 GB of RAM (if the Motherboard can accept it) with Windows XP can result in wasted RAM and, in some cases, may conflict with the PCI devices.
However, if you upgrade to Windows XP 64 or Vista, you’ll be able to address 4GB with no problem. In fact, you’ll be able to access almost 128GB of RAM!!!
So, I have configured my system with 3GB total RAM: 2 - 1GB in dual-channel and 2 - 512MB in dual channel. So far, it’s working fine. It’s important that the RAM pairs are matched for dual-channel mode (e.g., Ultra 1 GB 3200/400).