Windows 2000 has some excellent tools to help you analyse your system performance, and it is recommended that you investigate these before making changes to memory settings.

Edit the following registry key: 

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\MemoryManagement

DisablePagingExecutive

Set this to 1 to increase paging of the NT Executive to RAM, instead of the paging file. Only recommended with systems having 128 MB of RAM or greater.

IOPageLockLimit

The Windows 2000 default setting for this is 0, which is equivalent to 512 kb. The benefit of this tweak depends on how your system is configured, and there is no hard and fast rule: try setting it to 1024 kb, and then increasing it in 1024kb increments until you do not get any more performance gain. A good benchmark such as Winbench, will let you know if you are getting any improvement. For systems with more than 128 MB of RAM, 8192 kb and higher settings may produce performance gains.

I have had a report of severe slowdown in opengl performance with this tweak using a GeForce card. I have not experienced it myself with my own GeForce card, but I would be grateful to hear of your experiences. I will pursue this further in the near future. Also some people have reported problems with Easy CD Creator using this: for the small performance gain it may be better leaving this setting at its default! However I will leave it on the page as a warning to people who may encounter this tweak elsewhere.

LargeSystemCache

This option is enabled on Server, but not on Workstation. If you have over 128MB RAM set this to 1 to improve disk caching performance, if you have less then try it but you may see no gain, or a decrease in performance if you are multitasking. This is the NT equivalent of Windows 98 vcache setting.

For people with older systems, it is also worth looking at this Level 2 Cache tweak.