Asmo is right.
There is a upper page limit setting that must be entered in system.ini
It will tell windows9x/ME not to go above that page when using ram.
AFIR it needs to go into the [386enh] section and must be named MaxPhysPage = 40000 (that is for 1 gig, it is the hex number of "4096 k pages allowed).
Some have said to set it lower (maybe half?) and create a 512meg ramdisk then set the virtual memory to use the ramdisk instead of hard drive for casche/swap. Supposedly makes windoze run much faster, but I've never tried it.