The /maxmem switch in the Windows Boot.ini file


An undocumented /maxmem switch is mentioned on page 160 of Volume 3 of the Microsoft Windows NT Resource Kit. This switch enables you to specify the maximum amount of random access memory (RAM) memory that Windows NT may use.

This switch is undocumented because it works only on very specific configurations. The amount of memory must be contiguous. Microsoft has not committed to keeping the switch in any future releases of Windows.

More Information

This switch is placed at the end of the ARC path that is specified in the [operating systems] section of the Boot.ini file, as in this example:

multi(0)disk(0)rdisk(0)partition(1)\winnt="Windows NT" /MAXMEM=12
This example forces Windows NT to use only 12 MB of RAM, ignoring everything else above this. This switch may be valuable in troubleshooting parity errors, mismatched SIMM speeds, or other memory related problems.

Please note that you should never set the value of /maxmem to be less than 8, or Windows NT may not boot reliably. This switch is valid only on the x86 architectures, and is not available on the MIPS or Alpha platforms.

In Windows 2000 Professional, do not set /maxmem lower than 64 MB. In Windows 2000 Server and Windows 2000 Advanced Server, do not set /maxmem lower than 128 MB. In Microsoft Windows Server 2003, do not set /maxmem lower then 1024 MB. In other operating systems, check the minimum system requirements before you set /maxmem.