| By Scott Dunn |
No matter how much memory you have in your PC, you may not be getting the most out of your installed RAM.
A few little-known system tweaks can improve the way Windows manages memory, freeing up more RAM for your applications.
As described in an entry on the Microsoft Developer Network, all non-server 32-bit versions of Windows XP and Vista impose a memory limit of 4GB. Your system may allow you to install more than this amount of RAM, but with few exceptions, the extra memory won’t do Windows or your applications any good.
Moreover, even if you have 4GB of memory installed in your PC, you may not be able to use it all. For example, if your video card comes with 1GB of memory and you have 4GB of RAM, your system actually has 5GB of memory physically installed. But Windows will use only 4GB of that total, regardless.
It gets worse: according to a comment posted to the MSDN article, Windows itself is getting only 3GB because the video card gets 1GB. This happens because the memory aperture — a portion of system memory — is used to work with the video system.
Ways to break through Windows’ RAM ceiling
Fortunately, there are techniques you can use to get around Windows’ system-memory limitations. One method is to use Physical Address Extension (PAE), a feature of x86 processors that lets 32-bit operating systems overcome the 4GB memory limit.
Another MSDN article explains that 32-bit Windows operating systems support PAE. Even though XP and Vista still cling to the 4GB limit with PAE enabled, the feature may help you get back some of your unused RAM.