Increasing System Resources Available to Matlab

I am running Matlab on an old slow clunker at work. I only have 4 Mb or RAM. I know that there is a way to allocate more than 50% of the clock cycles to Matlab but I forgot how to do this?

[Jan]

4 MB RAM. Well. 4 MB RAM? Please define "old" and tell us the version and type of your OS and Matlab.

[Geoff]

My guess is a 386 running DOS and MatLab '84 =)