The new ROM SIMM in the Macintosh IIx is located 1/2 inch to the left of
the RAM SIMMs when looking at the machine from the front. The ROM SIMM is
about 3/8" taller than DIP-mounted SIMMs.
Because of its height, the new ROM SIMM may cause problems with the
installation of third-party, large capacity, full-height disk drives.
If DIP-mounted SIMMs currently cause installation problems with the
drives in question, then the ROM SIMM will make this problem more
pronounced.