Was researching the 3GB switch that could be used in the boot.ini file to extend Windows 2003 to more fully utilize memory when more than 3GB exists (think pre x64 days) – This is not recommended to be used with SBS and the SBS BPA will call your attention to this as is the case with why I did this research.
Overall this is a handy guide for many switch options.
Boot INI Options Reference
Published: November 1, 2006
There are number of BOOT.INI switches that are useful for driver developers that wish to test their drivers under a variety of different system configurations without having to have a separate machine for every one. For example, limiting the amount of memory NT sees can be useful for stressing memory loads, and limiting the number of processors for testing scalability. I’ve compiled a complete list of the options that BOOT.INI currently supports. This list is reproduced in the Startup, Shutdown and Crashes chapter of Windows Internals, where you’ll find more information about the boot process.
Note: to see what options a system has booted with examine HKLM\System\CurrentControlSet\Control\SystemStartOptions.