XP memory tweaks
Below are some Windows XP memory tweaks. They are located in the windows registry at: HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Control/ SessionManager/MemoryManagement

DisablePagingExecutive - When enabled, this setting will prevent the paging of the Win2k Executive files to the hard drive, causing the OS and most programs to be more responsive. However, it is advised that people should only perform this tweak if they have a significant amount of RAM on their system (more than 128 MB), because this setting does use a substantial portion of your system resources. By default, the value of this key is 0. To enable it, set it to 1.

LargeSystemCache - When enabled (the default on Server versions of Windows 2000), this setting tells the OS to devote all but 4 MB of system memory (which is left for disk caching) to the file system cache. The main effect of this is allowing the computer to cache the OS Kernel to memory, making the OS more responsive. The setting is dynamic and if more than 4 MB is needed from the disk cache for some reason, the space will be released to it. By default, 8MB is earmarked for this purpose. This tweak usually makes the OS more responsive. It is a dynamic setting, and the kernel will give up any space deemed necessary for another application (at a performance hit when such changes are needed). As with the previous key, set the value from 0 to 1 to enable. Note that in doing this, you are consuming more of your system RAM than normal. While LargeSystemCache will cut back usage when other apps need more RAM, this process can impede performance in certain intensive situations. According to Microsoft, the "[0] setting is recommended for servers running applications that do their own memory caching, such as Microsoft SQL Server, and for applications that perform best with ample memory, such as Internet Information Services."