I found this patch on net while surfing and tryed it.It will allow you to use up to 64gb of ram on your pc even limits are 3.25gb.I tested by myself on my pc and here are specs:
E8500
4GB RAM ddr2
Radeon 6670 gddr5
MS7519 P43
HDD 80GB 7200RPM
DVD Drive
Link
http://www.mediafire.com/file/cbj96q97joyjb1k/64+GB+of+RAM+patch.zip
Link to original link for download
https://mega.nz/#!ndsRFT4L!nOb6r6rq4kN7WcIsnrNOUYqAAclfu2zv3u2hTZS5eXk
Link to post on MSFN forum
http://www.msfn.org/board/topic/176149-nvidia-gtx-960-4gb-vram-on-windows-xp/?page=1
E8500
4GB RAM ddr2
Radeon 6670 gddr5
MS7519 P43
HDD 80GB 7200RPM
DVD Drive
Link
http://www.mediafire.com/file/cbj96q97joyjb1k/64+GB+of+RAM+patch.zip
Link to original link for download
https://mega.nz/#!ndsRFT4L!nOb6r6rq4kN7WcIsnrNOUYqAAclfu2zv3u2hTZS5eXk
Link to post on MSFN forum
http://www.msfn.org/board/topic/176149-nvidia-gtx-960-4gb-vram-on-windows-xp/?page=1