Performance will not increase if you install SIMMs rated at 60 ns in a
Macintosh Quadra because the SIMMs still will be accessed at the 80-ns
rate.
A problem with incorrect SIMM speeds is encountered when the SIMMs are too
slow for the system in which they are installed. For example, if you put
120-ns SIMMs in a system that requires 80-ns SIMMs, the CPU accesses the
120-ns SIMMs at the faster 80-ns rate. This causes those slower SIMMs to
overheat, produce random errors, and eventually fail completely.