The Simulator is just a repackaged version of the OS image that runs on our physical systems. We are able to release it as it is a minimal compile difference, and we use it for internal development as well. However, the downside is that it needs a lot of RAM, to simulate a writelog, and uses it write optimisation and deduplication buffers (etc).
For this reason, it is unlikely that a lower memory option will become available. For multinode simulation, I suggest using a spare or older server.