Source : Free On-Line Dictionary of Computing

Cache On A STick
     
         (COAST) {Intel Corporation} attempt to's
        standardise the modular {L2 cache} subsystem in
        {Pentium}-based computers.
     
        A COAST module should be about 4.35" wide by 1.14" high.
        According to earlier specifications from {Motorola}, a module
        between 4.33" and 4.36" wide, and between 1.12" and 1.16" high
        is within the COAST standard.  Some module vendors, including
        some major motherboard suppliers, greatly violate the height
        specification.
     
        Another COAST specification violated by many suppliers
        concerns clock distribution in synchronous modules.  The
        specification requires that the clock tree to each synchronous
        chip be balanced, i.e. equal length from edge of the connector
        to individual chips.  An unbalanced clock tree increases
        reflections and noise.
     
        For a 256 {kilobyte} cache module the standard requires the
        same clock be used for both chips but some vendors use
        separate clocks to reduce loading on the clock driver and
        hence increase the clock speed.  However, this creates
        unbalanced loading in other motherboard configurations, such
        as motherboards with soldered caches in the system.
     
        (1996-06-10)