The iso- prefix is used to indicate that a given difference measurement (or estimate) is reported while maintaining one or more other parameter(s) fixed.

Overview

The iso- prefix means 'equal'. The word originated from îsos in Ancient Greek which had a similar definition. The prefix is used to denote that a certain reported difference measurement or estimate was done while maintaining one or more secondary parameters fixed. In other words, an iso-comparison isolates one parameter from a number of parameters that affect each-other.

iso-comparisons are important for when different parameters may positively or negatively affect the primary parameter being compared. For example, if a CPU core may deliver improved performance versus a predecessor by utilizing a more advanced process node or by making use of more advanced circuit design techniques or both. Using an iso-process comparison would demonstrate how much benefits came from the design alone.

For example, "2nd-generation CPU core delivers 10% reduction in power at iso-performance and iso-process" means that the 2nd-generation CPU is able to achieve a reduction of 10% in its power consumption (under certain workload conditions) over the 1st-generation for identical performance level or capabilities on the same process node.

Comparison types

• iso-performance - A comparison that is done at a fixed performance level (e.g., at a fixed SPEC CPU2006/17 score).
• iso-power - A comparison that is done at a fixed power level (e.g., 1W/core)
• iso-area - A comparison that is done at a fixed physical silicon area
• iso-frequency - A comparison that is done at a fixed frequency (e.g., at 2 GHz for all devices)
• iso-throughput - A comparison that is done at a fixed throughput (e.g., same memory or PCIe bandwidth)

This list is incomplete; you can help by expanding it.

See also

• PPA