FREE LESSON · Semiconductors & electronics · 3 OF 4
CPU Timing, Heat and Chip Fabrication
Timing, heat, and fabrication — Why billions of switches are a systems problem
A chip must work across a distribution, not at one perfect point.
Fabrication produces variation in dimensions and electrical properties. Voltage and temperature change delay and leakage during operation. Designers close timing against defined corners and paths, distribute clocks, constrain power density, and use testing and redundancy to manage defects.
The manufactured object is statistical; the delivered contract must still be deterministic enough for software.
The critical path sets a clock ceiling
Between two state elements, combinational logic and wires consume time. The slowest relevant path must settle before the next capture edge, with margins for uncertainty. Shortening unrelated paths does not raise the safe clock; the critical path must change, or the work must be pipelined across more cycles.
System speed is constrained by the longest dependency, not the average operation.