Everyone knows that PCs sold today have more RAM than they did in the olden days. The question is, why? Applications grow hungrier and RAM prices keep falling, of course, but operating system bloat is the biggest reason. A review of systems that the PC World Test Center has evaluated since 1999 (see the chart below) reveals that the average RAM provision has grown from a little over 90MB to about 2GB, spiking whenever Microsoft releases a new version of Windows. For example, when Windows XP machines started appearing, system RAM increased, on average, from about 126MB to more than 286MB. When Windows Vista started shipping, our test PCs' RAM jumped from slightly more than 1GB to about 2GB. Windows' minimum system requirements ballooned from 16MB to 1GB over the same period. So when you are ready to upgrade your PC and your OS, you can assume that you'll need substantially more RAM.
RAM provisions (in megabytes) of desktops tested by the PC World Test Center have risen over time.