Sorry Rode,
 
" This is incorrect, Windows 2000 SP4 supports up to 2GB of RAM. 32 bit 
 Windows XP PRO SP2 supports up to 3.25GB of RAM."
 
We are both wrong, but I'll  stand on my statement, that 2GB is the highest you can have.

The following quote is from a Microsoft's WHDC page, http://tinyurl.com/6sho6

"Windows XP Professional and Windows Server 2003 Memory Support. The maximum amount of memory that can be supported on Windows XP Professional and Windows Server 2003 is also 4 GB. However, Windows Server 2003, Enterprise Edition supports 32 GB of physical RAM and Windows Server 2003, Datacenter Edition supports 64 GB of physical RAM using the PAE feature.

The virtual address space of processes and applications is still limited to 2 GB unless the /3GB switch is used in the Boot.ini file. When the physical RAM in the system exceeds 16 GB and the /3GB switch is used, the operating system will ignore the additional RAM until the /3GB switch is removed. This is because of the increased size of the kernel required to support more Page Table Entries. The assumption is made that the administrator would rather not lose the /3GB functionality silently and automatically; therefore, this requires the administrator to explicitly change this setting.

The /3GB switch allocates 3 GB of virtual address space to an application that uses IMAGE_FILE_LARGE_ADDRESS_AWARE in the process header. This switch allows applications to address 1 GB of additional virtual address space above 2 GB."

Yes, you can go higher, but this forum is to help those less inclined about computers.
Besides, most applications for the private/SOHO users, are not written with the flag /LARGEADDRESSAWARE. Nor, would I recommend someone to overwrite the boot.ini file to include the /3GB flag. One typing mistake, and their PC never works again.
Tim

            Do you want to signoff PCBUILD or just change to
                    Digest mode - visit our web site:
                   http://freepctech.com/pcbuild.shtml