The persistance of memory could be a problem if your melting clocks are swarmed by spooky ants. Wired has an article on magetic RAM http://wired.com/news/technology/0,1282,59559,00.html that fails to mention security implications. Obviously nonvolitile RAM presents a different security risk than RAM that forgets when powered off. Will future OSes have provisions to keep certain data out of MRAM banks, if MRAM doesn't completely displace DRAM? I doubt it. And shutting off your virtual memory swapping --useful today because of the gobs of DRAM machines have-- will no longer be useful for security. Not so obviously to the layman is how many times MRAM must be overwritten to keep the TLAs away. (Exactly analogous to scrubbing a disk.) While this is trivial to do for user-space, if the OS keeps copies of sensitive info this might require more than a huge malloc() & overwrites before shutdown.