What are the most significant memory parameters?

Hi,

Installed NW04s ABAP preview and it was rather slow.

Added memory to give it 2GB, still slow.

Added more memory, to give it 3GB and I noticed it doesn't use it. It seems to be configured to use around 1-1.5GB and that's that.

Can anyone point me to the most significant parameters to change to make it use the memory more effectively? (And where to change them).

Any input appreciated,

Mike