. Background of the Technology of the ‘336 Patent

Microprocessors are complex machines, with millions of individual parts whose operation requires coordination, both internally and with external components, for the chip to function properly. This coordination is performed by clock signals. U.S. Patent No. 5,809,336 (‘the ‘336 patent”), entitled “High Performance Microprocessor Having Variable Speed System Clock,” (Declaration of Eugene Mar in Support of Defendants’ Opening Claim Construction Brief (Mar Dec.), Ex. A) teaches the use of two independent clocks in a microprocessor system – an on-chip first clock to time the CPU, and a second independent clock to time the input/output (I/O) interface. This innovation was widely adopted by the industry and became fundamental to the increased speed and efficiency of modern microprocessors. Decoupling the system clock from the I/O clock allowed the clocks to run independently (or “asynchronously”), freeing the system clock, and thus the CPU, to run faster when needed (or more slowly to conserve power). This decoupling had the added benefit of reducing the sensitivity of the system as whole to temperature, voltage and manufacturing variations, since the on-chip first clock and the CPU could vary together in response to such variations, with minimal impact on the I/O interface due to the second clock domain.

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