Fine Tuning Memory with Windows XP Professional and Windows XP Professional 64-bit
Windows XP Professional
(Service Pack 2 is recommended. Service Pack 2 fixes a couple of critical bugs using the /3GB switch in the boot.ini file)
The maximum amount of memory that can be supported on Windows XP Professional is 4 GB. Using the /3GB switch in the boot.ini will cause the split between the user and system portions of Window XP Professional virtual address map from 2GB user, 2GB system to 3GB user, 1GB system (assuming that there is 4GB of memory installed) giving intensive applications a larger address space.
An Example of a Windows XP Professional boot.ini file with the /3GB switch added is shown in the figure below.
Windows XP Professional - 64 Bit
The /3GB switch is NOT needed in the boot.ini for Windows XP 64-bit.
Vendors claim compatibility with running FLUENT 32-bit on Windows 64-bit operating system. FLUENT has not yet endorsed or certified this on Windows XP 64-bit. In preliminary testing FLUENT is able to access up to 4 GB RAM per process when run on Windows 64-bit.
IMPORTANT NOTE: There is a known bug in using the /3GB switch and loading some video drivers. Additionally, some users have reported STOP errors when trying to start Windows XP Professional after the /3GB switch has been added to the boot.ini file. Microsoft claims that Service Pack 2 will resolve these issues. Download Service Packs directly from Microsoft's website.