You may be used to the procedure of doubling your system memory every few years or so, when a new operating system is introduced. We have seen this tradition with Windows 95, when the memory went from 4 to 8 MB in the mainstream or more recently with Windows XP when most users went from 128 MB to 256 MB. Windows Vista won't make an exception, even if you are already running your XP with a comfortable 1 GB of RAM.