Adding Memory to Vista
Someone recently asked me why they were not “seeing” all 4GB of RAM they recently added to their laptop computer. In general, the Vista 32-bit Operating System can support up to 4GB of RAM (64-bit can support up to 120GB, depending on the version, but that’s the topic for another post!). However, within that 4GB memory space, there needs to be room for your graphics adapter memory and the space used by the BIOS.
So, when viewing the basic information about your computer, you will see 4GB listed, but if you use a more detailed program, it may report a lower amount. For example, Windows Task Manager reports 3.069GB of RAM, but I know that my graphics adapter is using up to 1.278GB of RAM, so that may account for some of the difference.
For more technical information, check the following articles: http://support.microsoft.com/kb/929605, http://support.microsoft.com/kb/946003
Never fear though, Windows will use all available physical RAM available. If you have any questions about the optimal amount of RAM for your system, leave me a question in the comments and I will get back to you.