Max is limited by Windows..which allows up to a maximum of 2Gig RAM per operation, ie. MAX will only ever get a maximum of 2Gbytes under windows. With my personal experience, it crashes around 1.73Gbytes usage.
There is teh /3Gig switch which can be added to your windows startup ini file..it allows windows to use up to 3Gig per operation. a simple web search should show you how to do it.
This is all however resolved in the newer 64bit architecture versions of windows, which allow Much more RAM usage per operation.
I have 4Gig installed on my workstation, but i can never use more than 1.73 for MAX...