Theoretically, 32bits windows XP (Vista) should be able to support 4GB memory. However, for some reason M$ only allows 3GB memory under windows XP after sp2. Here is a way to fully utilize the other unsupported 1GB memory in your computer.
2. Double click ram4g.reg.
3. Execute ramdisk.exe. Select data size to 1GB and media type to fixed media. Click OK and restart your computer. You should be able to see an extra drive in “My computer”.
4. If you want to use this drive as virtual memory, it’s better to enable compression. To do this, simply right click on the drive and select “Format” from the pop-up menu. Select “enable compression” from the pop-up dialog.
5. Another application is using this drive as your browser cache.