I was curious myself and surprised I have no documentation of ramfs anywhere that I can find on my own Linux system, so I tried google and the first hit was
which explains it very well, including the answer to your question and alternatives. I think the file
containing that explanation is a common Linux file (not something special to that website). I just don't happen to have a copy on my system.
Edit, now there is a copy of it on my system. The file is actually
and it landed in the directory
when I installed the package linux-doc-2.6.22
But for your purposes, I think all that file tells you is to use tmpfs instead. See tmpfs.txt.gz in the same directory.