Subject:   -15- Why does my system tell me I need a revision C Memory
                Controller (MC) chip?
Date: 30 Apr 1994 00:00:01 EST

  Dave Olson <olson@sgi.com> explains:  Long, long story. Short
  synopsis: if you don't get memory errors, don't worry about it.

  Slightly longer: A number of vendors' 16 Mbit chips had a bug in
  them.  We found it, and they agreed it was their bug, but they were
  looking at a long, long DRAM spin time, so we worked around it in a
  new rev (rev C) of the memory controller.  The symptom was primarily
  parity errors; this could be confused with the other parity error
  problem we have, thus the warning message in 5.2.

  At least some of the vendors that had the problem should have fixed
  DRAM shipping by now, which is not to say that SIMMs you buy now have
  the new DRAMs on them. Not all vendors had the problem.