cache on a stick

Cache On A STick
COAST

   <architecture> (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)