# Windows XP Professional x64 and 4GB RAM?



## danodemano (Dec 10, 2007)

Alright, So with all the development and what not that I do, I decided to upgrade my system to 4GB of RAM. Also, due to software incompatibilities with Vista, I decided the my only real choice was Windows XP Professional x64 for my OS. I ran through the entire install, got all my drivers, everything seemed to be going well. I got my RAM today in the mail, slapped it in, checked the BIOS, and everything looked good. However, once I got into Windows, it only shows that I have 3GB available:









I checked with CPUZ to make sure that it was seeing the full 4GB and it was:









Now correct me if I'm wrong, but I had always thought that XP 64-bit supported something like 128GB of RAM....so why is my system not seeing the full 4GB???? Is there some option that I have to enable to allow Windows to use the full 4GB???

Any help would be appreciated, thanks!!


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## twajetmech (Jul 1, 2004)

The 128Gb memory address is a theoretical limit, chipset limitation may not allow you to take full advantge of the installed ram.....what laptop are we looking at here....what does the laptop mfg say about max supported memory.


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