When you run a program, dll files are introduced to memory for the running of the program. After the application using these same dll's has been closed, Windows Explorer caches these DLL files (Dynamic-Link Librarie) in memory for a period of time.
This is an inefficient use of allotted memory. To disable the caching of these DLL's,

1. Find the key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
   Windows\CurrentVersion\Explorer.


2. Create a new DWORD named "AlwaysUnloadDLL" and set the default Decimal value to equal "1" to disable Windows caching the DLL in memory.


3. Restart Windows for the change to take effect.


Before I tried this hack I was using 142 MB's out of 512MB's of RAM after a cold boot. I tried the trick and checked the performance monitor of XP's Task Manager after a cold boot and I was using 100 MB's. Quite a difference wouldn't you say?

There's no need to install any kind of memory manager with this trick.