HP Vectra XU 6/XXX Optimization Manual page 4

NOTE
Inside the Processor
Internally, your PC's processor performs tasks by breaking them down into sub-tasks. Each of
these sub-tasks requires a number of clock cycles to complete.
The Pentium Pro processor integrates some functions that were performed by external
components in previous generations of PCs; level-two cache memory is an example of one of
these functions. This means that the Pentium Pro processor can perform a significant
proportion of its work internally, without needing to access other PC components through the
local bus.
By using a faster clock for internal operations than for external (local bus) operations, the
Pentium Pro processor accelerates the work it performs internally. Since internal operations
represent much of the processor's total activity, the effect of this acceleration is a significant
improvement in overall processor performance.
The advanced Pentium Pro processor installed in
your PC provides the best performance when used
with 32-bit operating systems and applications.