Amdahl/Case Rule: A balanced computer system needs about 1 MB of main memory capacity and 1 megabit per second of I/O bandwidth per MIPS of CPU performance.

90/10 Locality Rule: A program executes about 90% of its instructions in 10% of its code.

Bandwidth Rule: Bandwidth grows by at least the square of the improvement in latency.

2:1 Cache Rule: The miss rate of a direct-mapped cache of size N is about the same as a two-way set- associative cache of size N/2.

Dependability Rule: Design with no single point of failure.

Watt-Year Rule: The fully burdened cost of a Watt per year in a Warehouse Scale Computer in North America in 2011, including the cost of amortizing the power and cooling infrastructure, is about $2.